BuddyPress.org

It’s not a dummy question but there is little to go on, the best I can suggest is that you start of afresh create a child theme (which it sounds as though you have done) and start to add your old styles in and try and re-create the previous layout based on the new default theme, more than this and you would need to provide far more detail but i don’t think it would help, just a case of getting stuck in really and asking questions as and when you get stuck.