Download a mod, then double click it in your downloads bar when it's done. (the little down arrow in the top right.) Make sure you press the PC/Mac button though. @SomeRandomNerd

But how do you mod it?

Yes! You can Mr.Lucky.

@SomeRandomNerd

I bought the game on steam . Can I mod the steam version

Yeah... I got it on the Apple store, but i have a steam account, so I could do something with that maybe?@BaconAircraft

However, he could get a steam key if he have proof of purchase on the Mac AppStore; I'm pretty sure. @WNP78

Ok, my mistake. @WNP78

@Gestour not if it's from the Mac app store.... Read the guide again

The Mac App Store version of the game does not support modding due to Apple's App Store policies. Sorry.

The PC mods work on OSX. FYI @IStoleYourMeme

Use the PC/Mac button...

i made this thread for ios users but it should be able to help you too:
clicky clicky