There are two varieties of .NET now: .NET framework, and .NET CORE. If the project
is looking for "dotnet.exe", then it is a .NET CORE project. This means you need to check your Visual Studio install to make sure you have .NET CORE support installed.
I think the default is .NET framework. I think there is a Nuget way to get .NET CORE or a VS setup tweak to add it. Sorry, I'm not in front of Visual Studio at the moment, so I can't give you a step-by-step. You should be able to Google it.
If you open the Visual Studio Installer you can download the .NET Core components to help you build the app.