A SMAPI mod is a compiled library (DLL) with an entry method that gets called by SMAPI, so let's set that up.
# Open Visual Studio 2017 or MonoDevelop.
# Create a solution with a .NET Framework class library project (see [[Modding:IDE reference#create-project|how to create a project]]). '''Make sure you choose .NET Framework, not .NET Core or .NET Standard.'''
# Change the target framework to .NET Framework 4.5, 4.5.1, or 4.5.2 for best compatibility (see [[Modding:IDE reference#set-target-framework|how to change target framework]]).