Creat a new page. Name it whatever and publish. Go to buddypress ->pages and select just created page as search’s functioning page. But I am not sure search require a seperate page. Remember to subset the page to an already published page as a sub page
I am going to have an headache with this “privacy” thing. YOU CANT MONETISE A PRIVATIZED SITE WITH ADSENSE!.
If your after privacy, I recommend Elgg. I left it because of that stupidly built feature. With that free script a user can even privatize a forum post.
Before installing buddypress i created a page named “group forums” and when installing buddypress forums, assigned it as its sole page. Later seperately installed bbpress. No harm at all