Want to change BP-Social theme search function

I'm using the BP-Social theme and I don't want to use the theme's search function on the site because non-members don't have access to the search functionality.

I would like to either just use the regular WordPress search function, or Google custom search. But I don't know what to change to use the WordPress search function, and when I try to set up Google custom search, the results redirect to "member" page, but nothing comes up.

I just want my visitors to be able to search the posts on my site. I know about the Post Indexer and Global Site search, but it only shows posts since the Post Indexer was installed, and I want to be able to search all of my posts.

Can anyone help me to solve this problem?