Joining game through application

Basically, I have a place ID which I would like to join from at least 2 accounts. I have the ROBLOSECURITY cookie of all the accounts, and I’m not too sure how to join games programmatically. I have seen it done before, for example in Roblox Account Manager.

Any help at all would be great! Thanks!

not 100% sure, but I imagine that the Game join API endpoints would be relevant:

I tried using join-game and join-game-instance but they don’t actually take you to the game afaik (maybe I’m doing it wrong).

Any other ideas as to how to do this, or as to how to use the GameJoin API?