As would be Pathfinder GM and wanting to give game access through the drop down menu, how do I let my game be joined?

Maybe I'm just not seeing it. For the player it's easy. You go the menus at the top of the screen, click on games and click on join a game. Now, as a prospective GM, I've got my trial one shot up   and ready  (at this stage I'm hoping to run it a few times)   and want to link to the join a game option from the other side. How do I do that ? Is there a guide somewhere that shows how this should be done or other advice? Thanks guys!

It's ok I'm sorted now, though I'm surprised there's not some similarly readily accessible guidelines on this.