Hi MoeskiB!
Yeah, you can't transfer save from the .2 version since .3 is a complete overhaul, which means the old system from .2 is literally reworked in .3!
and as for the mod, just put the folder inside the "game" folder, and if you see the mod inside the mod tab, then its good to go!
If its not, please contact me on discord to show further about the issue! ^^
Cheers!