I have a full campaign of 12 players. I've had people leave our group and new people who want to join.

I haven't been able to find out how to remove players from a campaign. How can I do this?

There should be a Remove button option under each player in the campaign. You can also choose Deactivate if you want to keep them in the campaign but not have them count towards the 12 player limit. 

Thanks!

Hello, I'm also struggling to do this, I can see the deactivate under a character made, but I can't find the remove button for the player.

If you're the DM there's a REMOVE option right next to deactivate when you open it up from the MY CAMPAIGNS area.

If you're the player trying to remove your own character there's a LEAVE option when you open up the campaign from the MY CAMPAIGNS area.