Me not see how do in resources, guides, forum, or rules.

Seriously though, there's no info on how to do anything for these coop runs.

Edit: Here's how do thing
Troubleshooting: Sometimes you won't see each other's characters once you're in the game. If this happens, try clicking the "Set Char Tick Rate" button a couple times once you have some down time in the Garage and see if they appear.