1) Go to assignments, general aircraft commands, and look for the key assignement for aircraft pushback.
2) You don't. If you download a scenery it will tell you if you if the jetways move, and the appropriate action to operate them.
3) Again, go to assignments, general aircraft commands, and look up the key assignment to open the door.
Next time, try punctuating your sentences. No one likes to translate what you have to say.
Holy sh*ts and burritos.