Make an alternative method while cloning (#4333)

* Make an alternative method while cloning skywalking project and sync submodules

* Add language type for code block

* Intend code blocks under list block

* Make list number same

* Move a tip about building from source codes.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

docs/en/guides/How-to-build.md

@@ -6,7 +6,7 @@ This document helps people to compile and build the project in your maven and se
 
 ### Maven behind Proxy
 If you need to execute build behind the proxy, edit the *.mvn/jvm.config* and put the follow properties:
-```
+```properties
 -Dhttp.proxyHost=proxy_ip
 -Dhttp.proxyPort=proxy_port
 -Dhttps.proxyHost=proxy_ip
@@ -17,11 +17,22 @@ If you need to execute build behind the proxy, edit the *.mvn/jvm.config* and pu
 
 ### Build from GitHub
 1. Prepare git, JDK8 and maven3
-1. `git clone https://github.com/apache/skywalking.git`
-1. `cd skywalking/`
-1. Switch to the tag by using `git checkout [tagname]` (Optional, switch if want to build a release from source codes)
-1. `git submodule init`
-1. `git submodule update`
+1. Clone project
+
+    If you want to build a release from source codes, provide a `tag name` by using `git clone -b [tag_name] ...` while cloning.
+    
+    ```bash
+    git clone --recurse-submodules https://github.com/apache/skywalking.git
+    cd skywalking/
+    
+    OR
+    
+    git clone https://github.com/apache/skywalking.git
+    cd skywalking/
+    git submodule init
+    git submodule update
+    ```
+   
 1. Run `./mvnw clean package -DskipTests`
 1. All packages are in `/dist` (.tar.gz for Linux and .zip for Windows).
 
@@ -81,69 +92,69 @@ Refer to [Build docker image](../../../docker) for more details.
 **NOTICE**: If you clone the codes from GitHub, please make sure that you had finished step 1 to 7 in section **[Build from GitHub](#build-from-github)**, if you download the source codes from the official website of SkyWalking, please make sure that you had followed the steps in section **[Build from Apache source code release](#build-from-apache-source-code-release)**.
 
 1. Import the project as a maven project
-2. For supporting multiple source directories, you need to add the following configuration in `skywalking/pom.xml` file:
-```
-<plugin>
-    <groupId>org.codehaus.mojo</groupId>
-    <artifactId>build-helper-maven-plugin</artifactId>
-    <version>1.8</version>
-    <executions>
-        <execution>
-            <id>add-source</id>
-            <phase>generate-sources</phase>
-            <goals>
-                <goal>add-source</goal>
-            </goals>
-            <configuration>
-                <sources>
-                    <source>src/java/main</source>
-                    <source>apm-protocol/apm-network/target/generated-sources/protobuf</source>
-                    <source>apm-collector/apm-collector-remote/collector-remote-grpc-provider/target/generated-sources/protobuf</source>
-               </sources>
-            </configuration>
-        </execution>
-    </executions>
-</plugin>
-```
-3. Add the following configuration under to let eclipse's M2e plug-in supports execution's solution configuration
-```
-<pluginManagement>
-    <plugins>
-    <!--This plugin's configuration is used to store Eclipse m2e settings 
-    only. It has no influence on the Maven build itself. -->
-        <plugin>
-            <groupId>org.eclipse.m2e</groupId>
-            <artifactId>lifecycle-mapping</artifactId>
-            <version>1.0.0</version>
-            <configuration>
-                <lifecycleMappingMetadata>
-                    <pluginExecutions>
-                        <pluginExecution>
-                            <pluginExecutionFilter>
-                                <groupId>org.codehaus.mojo</groupId>
-                                <artifactId>build-helper-maven-plugin</artifactId>
-                                <versionRange>[1.8,)</versionRange>
-                                <goals>
-                                    <goal>add-source</goal>
-                                </goals>
-                            </pluginExecutionFilter>
-                        </pluginExecution>
-                    </pluginExecutions>
-                </lifecycleMappingMetadata>
-            </configuration>
-        </plugin>
-    </plugins>
-</pluginManagement>
-```
-4. Adding Google guava dependency to apm-collector-remote/collector-remote-grpc-provider/pom.xml files
-```
-<dependency>
-   <groupId>com.google.guava</groupId>
-   <artifactId>guava</artifactId>
-   <version>24.0-jre</version>
-</dependency>
-```
-5. Run `./mvnw compile -Dmaven.test.skip=true`
-6. Run `maven update`. Must remove the clean projects item before maven update(This will be clear the proto conversion Java file generated by the compiling)
-7. Run `./mvnw compile` compile collector-remote-grpc-provider and apm-protocol
-8. Refresh project
+1. For supporting multiple source directories, you need to add the following configuration in `skywalking/pom.xml` file:
+    ```xml
+    <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <version>1.8</version>
+        <executions>
+            <execution>
+                <id>add-source</id>
+                <phase>generate-sources</phase>
+                <goals>
+                    <goal>add-source</goal>
+                </goals>
+                <configuration>
+                    <sources>
+                        <source>src/java/main</source>
+                        <source>apm-protocol/apm-network/target/generated-sources/protobuf</source>
+                        <source>apm-collector/apm-collector-remote/collector-remote-grpc-provider/target/generated-sources/protobuf</source>
+                   </sources>
+                </configuration>
+            </execution>
+        </executions>
+    </plugin>
+    ```
+1. Add the following configuration under to let eclipse's M2e plug-in supports execution's solution configuration
+    ```xml
+    <pluginManagement>
+        <plugins>
+        <!--This plugin's configuration is used to store Eclipse m2e settings 
+        only. It has no influence on the Maven build itself. -->
+            <plugin>
+                <groupId>org.eclipse.m2e</groupId>
+                <artifactId>lifecycle-mapping</artifactId>
+                <version>1.0.0</version>
+                <configuration>
+                    <lifecycleMappingMetadata>
+                        <pluginExecutions>
+                            <pluginExecution>
+                                <pluginExecutionFilter>
+                                    <groupId>org.codehaus.mojo</groupId>
+                                    <artifactId>build-helper-maven-plugin</artifactId>
+                                    <versionRange>[1.8,)</versionRange>
+                                    <goals>
+                                        <goal>add-source</goal>
+                                    </goals>
+                                </pluginExecutionFilter>
+                            </pluginExecution>
+                        </pluginExecutions>
+                    </lifecycleMappingMetadata>
+                </configuration>
+            </plugin>
+        </plugins>
+    </pluginManagement>
+    ```
+1. Adding Google guava dependency to apm-collector-remote/collector-remote-grpc-provider/pom.xml files
+    ```xml
+    <dependency>
+       <groupId>com.google.guava</groupId>
+       <artifactId>guava</artifactId>
+       <version>24.0-jre</version>
+    </dependency>
+    ```
+1. Run `./mvnw compile -Dmaven.test.skip=true`
+1. Run `maven update`. Must remove the clean projects item before maven update(This will be clear the proto conversion Java file generated by the compiling)
+1. Run `./mvnw compile` compile collector-remote-grpc-provider and apm-protocol
+1. Refresh project