Add instructions to the README.md file (#142)

* Add instructions to the README.md file

* Update README.md

Co-authored-by: Robert Biter <robert.biter@zalando.de>

---------

Co-authored-by: Robert Biter <robert.biter@zalando.de>

README.md

@@ -56,6 +56,21 @@ Visit the [releases page](https://github.com/1dot13/source/releases) to download
    (those issues can occur due to the combination of old game and modern OS/hardware, cnc-ddraw helps to avoid those) 
 
 
+### Visual Studio setup
+
+1. Run `Visual Studio 2019` or newer.
+2. Clone and open the location with the source code using one of these two options:
+    * Click `Clone a repository`
+        * Enter `git@github.com:1dot13/source.git` or `https://github.com/1dot13/source.git` in the Repository location field, select the path you want to clone the repository to and click `Clone`.
+        * Double-click on `Folder View` in the `Solution Explorer`
+    * Click `Open a local folder`
+        * Use this option if you already cloned the repository yourself.
+3. Visual Studio will automatically detect the CMake configuration files and will run the CMake generation. There will bet a CMake error in the logs saying `No existing preset was found, copied a preset template to [some_path]`. This is normal and only happens once.
+4. Click on the dropdown that says `x64-Debug` and select `Manage configurations...`. This should trigger Visual Studio to load the `CMakeUserPresets.json` file it just copied. Now you can close the window for managing the configurations.
+5. The `x64-Debug` option should have been replaced by `1dot13 Debug`. Click it and select `Manage configurations...` again. Here is where you configure the language for the built executables as well as which ones to build, Most important, here is where you set `CMAKE_RUNTIME_OUTPUT_DIRECTORY` to the path to your JA2 1.13 installation. This will be used for debugging. Note that the path needs to have a working 1.13 installation, and that includes the 1.13 game data.
+6. You can use `Build -> Build All` to build the executables you selected in the configuration.
+
+
 ### Reports
 
 For more information and reports, visit [Bug reports at Bear's Pit Forum](http://thepit.ja-galaxy-forum.com/index.php?t=thread&frm_id=216&) or join the [Bear's Pit Discord](https://discord.gg/GqrVZUM "Bear's Pit Discord")