All the instructions on the main mod page. If you fancy messing around with the console, you can download the mod at the link above.
Players who've used this mod already say that all the basic commands work though - so simple things like adding credits, XP and enabling/disabling noclip should work just fine. It's worth noting that not all of the commands will work perfectly, as some code will have been changed for the Legendary Edition versions of the games. You can also give a specific power (like a biotic or tech ability) to a character, or bring up the squad selection screen mid-level (though the wiki says this one can break music and dialog). Some interesting commands for ME2 include being able to kill all enemies in the area you're in, as well as kill Shepard if you want to. The in-game console works in both Mass Effect 1 and Mass Effect 2, and you can find a complete list of codes on the games' wikis ( ME1 over here, and ME2 over there).
