re-implementation of an "amazing" game server

You are expected to already have the .NET CLI installed, and to install the required frameworks as needed during the build process.

Place the game's Assembly-CSharp.dll into a directory called libs.

mkdir libs
cp /path/to/Assembly-CSharp.dll libs

Then simply build:

dotnet build

Or run:

dotnet run

Visual Studio Code is generally recommended for development. You will need the C# Dev Kit extension for syntax highlighting and IntelliSense.