Until we have Steam Workshop support the only way to apply mods is to drop the directory into Soulash/data/mods/
Then go into the game, in the main menu select "Mods" and mark mods that you want to run when creating a new game. Click accept and start a new game.

How do i mod races?

You can edit characters.json file in your mod to add or modify existing races. You can get some help on our discord modding channel if you need it.