bbPress.org

I think you can only make a thread sticky. At the bottom of the thread, when you are logged in, you will see this link:

[Stick topic (to front)]

Click either “Stick topic” or “to front” and the thread will be sticky. If you’re not admin (keymaster) I don’t think you see that.

I don’t think the links are visible while creating a new post or thread. So make your post, then view it and look at the bottom of the page; you’ll see the links you need.