>>716376591
On RainDB they have mirrors for all the legacy mods and the tutorial section lines installation (just need to double make sure to take note of dependencies)
the file structure for 1.5 vs 1.9 is different so make sure you're using the right one.

Also jolly coop is couch coop, if you want to play over net Rain Meadow on workshop is your friend and doesn't need downpour, there's also split screen coop mod which also doesn't need downpour.

For legacy, if you've ever modded a unity game with BepInEx it's the same as all the others.