How do I uncheck 'manually manage music and videos?

I just upgraded to 12.0. When I sync now, and go to Summary, I used to have it checked to 'sync only checked songs and videos'. That was still there, but now the list of playlists doesn't show like it used to. I tried unchecking and checking different things. I ended up with 'manually manage music and videos', which it says will erase existing content and replace with my library - I don't want this! I want my playlists listed like it used to be so I can check or unchecked what I want synced. How do I get this back?