Put the GTA5 Mod Switch.exe anywhere you want and launch.
you will need to set the location of GTA V by going to settings. If you change mod folder location be sure to keep it in the same drive as GTA V location.
It does not matter if you put mods in gta location before launching this app, or put the mods in the gta5modsfolder after.
This will work with all mods except rpf mods.
Only tested on retail version – Steam is unknown.