Improve build instructions (#948)

Author: pascalberger

docs/input/documentation/contributing/how-to-build.md

@@ -3,16 +3,67 @@ title: How to build addins
 description: Instructions how to build individual Cake Issues addins.
 ---
 
-To build this a package we are using Cake.
+## Building addins
 
-On Windows PowerShell run:
+Ensure the following prerequisites are fulfilled:
 
-```powershell
-./build
-```
+* Latest .NET version installed
 
-On OSX/Linux run:
+To build the addins and run unit tests [Cake] is used:
 
-```bash
-./build.sh
-```
+=== ":material-microsoft-windows: Windows"
+
+    ```powershell
+    .\build.ps1
+    ```
+
+=== ":material-apple: macOS"
+
+    ```bash
+    ./build.sh
+    ```
+
+=== ":material-linux: Linux"
+
+    ```bash
+    ./build.sh
+    ```
+
+To run only part of the build a task can be passed using the `--target=<TASK>` syntax:
+
+| Task                    | Description                                                                                                                         |
+|-------------------------|-------------------------------------------------------------------------------------------------------------------------------------|
+| `DotNetCore-Build`      | Builds all addins                                                                                                                   |
+| `Create-NuGet-Packages` | Builds an creates NuGet packages for all addins. The NuGet packages are available in the `BuildArtifacts\Packages\NuGet` directory. |
+| `Test`                  | Builds all addins and runs unit tests. Coverage report is available in the `BuildArtifacts\TestCoverage` directory.                 |
+
+## Building and running website locally
+
+Ensure the following prerequisites are fulfilled:
+
+* Latest .NET version installed
+* Python 3 installed
+
+To build and serve the website [Cake] is used:
+
+=== ":material-microsoft-windows: Windows"
+
+    ```powershell
+    .\build.ps1 --target=website
+    ```
+
+=== ":material-apple: macOS"
+
+    ```bash
+    ./build.sh --target=website
+    ```
+
+=== ":material-linux: Linux"
+
+    ```bash
+    ./build.sh --target=website
+    ```
+
+Website is available on `http://127.0.0.1:8000/`
+
+[Cake]: https://cakebuild.net/