[Solved] How to remove some things at the top of the forum page
If you mean to the menu bar with "forums" "members" "register" and "login", You can disable it easily.
Just go to you control panel, appearance->menus->choose the wpforo navigation menu->uncheck the "wpforo menu" on the bottom of the page and hit save.
Hopefully I solved your problem ! 🙂
Just saw the screenshot and the thing you want to remove is about the theme, Check the customize under appearance, Search for header or something like that.