A toy recommendation system built in C# using .NET Core.
First off, make sure you have both the .NET Core 3.0 SDK and runtime installed on your machine for whichever operating system and architecture you're running.
After loading the solution via Visual Studio, either hit F5 or click the green play button in the toolbar to build and launch the console application.
Navigate to the folder or directory containing the project, then run dotnet build and, provided there are no build errors, dotnet run.