1a. Well press start in the lobby
1b. Click over to the second tab and go down to where is says appearance.
1c. Once there you can change the way your guy looks judging on what costumes you unlocked and so forth.

2a. Go to theater mode
2b. Que up one of the past 25 matches you have played in
2ba. To queue up a video just go down to where it says ex. "Team Slayer on Valhalla" and select that which will bring up a list of your past 25 matches.
2c. Pull up the movie and start it
2d. During the movie press the "Y" button or "Start" button, one of the 2 to bring up a key legend.
2e. Press "X" button to bring up a on-screen display that will allow you to record certain parts and take screenshots. You can then save screen shots and so forth.

I hope that explains it. The manual doesn't explain crap and it took me about a half hour to figure all that crap out.