[doc]intro to the compiling variables-EN (vesoft-inc#1466)

* intro to variables

* laura

* code verification

Co-authored-by: dutor <440396+dutor@users.noreply.github.com>

docs/manual-EN/3.build-develop-and-administration/1.build/1.build-source-code.md

@@ -66,8 +66,8 @@ bash> source ~/.bashrc
 ```bash
 bash> mkdir build && cd build
 bash> cmake ..
-bash> make
-bash> sudo make install
+bash> make -j$(nproc)
+bash> sudo make install -j$(nproc)
 ```
 
 Or you can build the release version.
@@ -76,8 +76,58 @@ Or you can build the release version.
 
 ```bash
 bash> cmake -DCMAKE_BUILD_TYPE=Release ..
-bash> make
-bash> sudo make install
+bash> make -j$(nproc)
+bash> sudo make install -j$(nproc)
+```
+
+#### Instructions on Variables
+
+- CMAKE\_INSTALL\_PREFIX: specifies the installation directory.
+
+If you specify an installation directory during cmake, the `make install` installs **Nebula Graph** to the specified directory.
+
+For example, the following commands install **Nebula Graph** in the `/home/test` directory.
+
+```bash
+bash> cd nebula/build
+bash> cmake -DCMAKE_INSTALL_PREFIX=/home/test ..
+bash> make -j$(nproc) && make install -j$(nproc)
+```
+
+- NEBULA\_BUILD\_VERSION: set the version number for the binary files
+
+For example, the following commands set the version number to `1.0.0`.
+
+```bash
+bash> cd nebula/build
+bash> cmake -DNEBULA_BUILD_VERSION="1.0.0" ..
+bash> make -j$(nproc) && make install -j$(nproc)
+```
+
+The following command checks the version number of the compiled binary files in `/usr/local/nebula/bin/` directory.
+
+```bash
+bash> /usr/local/nebula/bin/nebula --version
+```
+
+- ENABLE\_TESTING: specifies whether to compile the UT code.
+
+The default value is ON. If you don't want to compile, set it to OFF during cmake with the following command.
+
+```bash
+bash> cd nebula/build
+bash> cmake -DENABLE_TESTING=OFF ..
+bash> make -j$(nproc) && make install -j$(nproc)
+```
+
+- ENABLE\_ASAN: Add AddressSanitizer when compiling.
+
+The default value is OFF. You can set it to ON during cmake with the following command.
+
+```bash
+bash> cd nebula/build
+bash> cmake -DENABLE_ASAN=ON ..
+bash> make -j$(nproc) && make install -j$(nproc)
 ```
 
 #### **Building Completed**

docs/manual-EN/4.contributions/how-to-contribute.md

@@ -97,32 +97,28 @@ git push --force origin master
 
 #### Edit the Code
 
-You can now edit the code on the `myfeature` branch. We are following [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html).
+You can now edit the code on `myfeature` branch. Please be noted that we are following [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html).
 
-#### Run Stand-Alone Mode
+### Verifying Your Code
 
-If you want to reproduce and investigate an issue, you may need
-to run Nebula Graph in stand-alone mode.
+#### Compiling the Source Code
 
-```bash
-# Build the binary.
-> make server
+Please refer to the [build source code](../3.build-develop-and-administration/1.build/1.build-source-code.md) documentation to compile.
 
-# Run in stand-alone mode.
-> nebula-graphd
-```
+#### Code Verification
 
-Then you can connect the **Nebula Graph** console to your local server
+- Replace the binary files
 
-```bash
-> nebula
-```
+    The compiled binary files of the three services are in `nebula/build/src/daemon/_build/` directory. The compiled console is in `nebula/build/src/console/_build` directory. You can replace the binary files in the bin directory, restart the services and verify.
+- Add unit tests
 
-#### Run Test
+    There is a `test` directory in the modified code module. You can add unit tests in it, then compile and run the unit tests. Please make sure your submitted codes pass all the unit tests.
+- Run all the unit tests
 
-```bash
-# Run unit test to make sure all tests passed.
-```
+    ```bash
+    cd nebula/build
+    ctest -j$(nproc)
+    ```
 
 ### Step 5: Keep Your Branch in Sync