Where do I get a group token from to register new users?

[dataprolet]

The registration of new users is kind of confuseing. I want them to join an existing group and for that a group token is necessary. But where do I get that token from?

[huntfx]

Annoyingly this is one of the top results when trying to find out the info.

I managed to find it anyway: Settings > User Settings > Get Invite Link, then it fills in the token automatically for you.