To get the expert mode, press Back, Forward, Back, Forward, then Forward, Back, Forward, Back at the how to play screen.
In 2 player versus, both players should choose their fighters. On the loading screen before the match starts, both players should hold the B and C buttons.
Press back, forward, back, forward, forward, back, forward, back on the DPAD at the ''How to Play'' screen
Go into versus mode and select the two fighters. When the ''Now Loading'' screen comes up, hold B+C on both controllers until the match begins.