Pre moves and bullet tournaments!!!

I don't know if everyone has this ploblem but ,I use an iPhone 4s app to play chess on chess.com. I can't play in the live tournaments I don't guess I've tried . If its possible can you tell me how to please. Further more I can't make pre-moves either and if that's possible let me know thanks ... P.s watch the YouTube channel ,chessexplained , I lobe this guys games and explanations.