Sibwarra208

I'm new to the way Collection works, so it's possible I'm just doing something completely wrong. How would I go about selecting the mission directly within the playlist? If I play Pillar of Autumn, it just continues on from that point.

I have spent the past several days running through the games in order via the Saga playlist. Once I completed Halo 3, I decided to be done for a bit before I took on Halo 4. When I loaded the playlist back up, it said my current place was Pillar of Autumn, from Halo CE. The completion meters on each mission I'd done were visible, and it says the next mission to be played is the Prologue of Halo 4. However, when I press resume, it loads PoA. How can this be fixed?