If you want to do long flights, you really ned to learn how to program te FMC and use it to plan your flight. You should start with this Tutorial flight by aussie and take a look at the 757 Tutorial Videos by Bob Markey.

After that you can ask for anything you need help with. Try searching the Forum before that though. Many others have ask the same questions, and been given answers, that you will probably want/need to ask. ;)

Mark