Open the link: https://visualstudio.microsoft.com/vs/mac/
 
Set Visual Studio to Mac:

Download the MonoGame extension from the link:
https://github.com/MonoGame/MonoGame/releases/tag/v3.8.1
 
The file is downloaded.
We will install this file in Visual Studio like this:

 
In the menu, click on Visual Studio, and then click on the Extensions:

 
Click on Install from file and select the downloaded MonoGame file:

 
Click on the Install button:

Read more: docs.monogame.net/articles/getting_started/ ...
 

Open the link in Google Chrome: https://github.com/EvgenProjects/MyGame_AnimalGo_MonoGameCSharp
Click on Code and download the code

In Visual Studio open the file MyGame_AnimalGo_MonoGame.sln