Cross-posting

Ok so idk if I am missing something, I see the checkbox where it says you can enable cross-posting, so that blog posts go onto the forum, but I don’t see where it asks you to choose a forum to make the posts in?

Please tell me if I am just being a noob and missing something, this is driving me nuts!

https://ww.wp.xz.cn/plugins/wp-phpbb-bridge/