1. Select all the extra stuff - titles, stills, etc. - and delete them. Leave only the video and audio clips.
2. Create a second sequence, and nest the first sequence into it. Right click>Multicam>Enable
3. Click the wrench under the Program Monitor, select Muli-Camera.
4. Cut away.
5. Change the Program Monitor back to Composite. Go through the sequence a second time and make any necessary tweak to the cut points.
6. Now you can add your titles, stills, etc.
Yes, what Jim said...
or if you really want to leave all your little stills and titles there and not have to add them later then alt+select all the video clips only and right click>nest. You can select all the audio clips too but I usually leave them there so I can see them all individually (personal preference) and I never have audio follow video in my edits so it's not necessary. Then right click>Multicam>Enable and proceed with #3 from Jim's list. I actually prefer to ignore the wrench and add that one touch little multicam toggle icon to the program monitor which it appears you've already done so you just need to select the far right icon on the bottom of your program window next to the little camera icon. That's the multicam toggle. Multicam cutting now takes place in the Program Window instead of the Source Window like it was in CS6. Oh also, the little "tweaks" that Jim mentioned can be easily done with the Rolling Edit Tool (Shortcut: N) You'll see. Good luck!