Building

First off, ensure that your system has an up to date version of Visual Studio installed alongside the .NET Framework 3.5 development tools, as well as Unity 5.6.3 and a copy of Freedom Planet 2 itself that is set up for modding with BepInEx and FP2Lib (using the Freedom Manager tool can set the game and libraries up automatically for you).

Open the solution file in VS2022 then go to Tools > Options and select Package Sources under the NuGet Package Manager category. Then add a package source called BepInEx with the source url set to https://nuget.bepinex.dev/v3/index.json.

Next, go to the Assemblies category in the Dependencies for the project, then delete the Assembly-CSharp, FP2Lib and Rewired_Core references. Right click on the Assemblies category and click Add Assembly Reference..., then click Browse... and navigate to Freedom Planet 2's install directory. Open the FP2_Data directory, then the Managed directory and select the Assembly-CSharp.dll and Rewired_Core.dll files, then click Add. Choose Browse... again and navigate to the install location of FP2Lib's DLL (likely within the BepInEx\plugins\lib directory) and select it. Click Add, then click OK to close the Reference Manager.

You should now be able to right click the solution and choose Rebuild to build the mod.