hmm, so many questions...
Guides -
The Unofficial Guild Wars Site - GWOnline.Net - Wiki, Datbases, Forums (In the forums)
Pre-Searing i guess, It means the peace-ful (dam thing censors pea***ul) time ur living in is gonna end, not gonna spoil why, but after this, you cant come back
You should get out of pre-searing after you've done around 95% of the quests there
You should try and do all quests, some that are really hard or some that are really boring, you can skip, that just means you have to do some more training in searing, but it will be easier since they are higher level.
In pre-searing, there are, give or take, 6 "areas". Area around Ascalon, Area around Ashford Abbey, Wizard's Folly, Area around the giant balthazar statue (including the mansion place), Regent Valley and the catacombs. Try and get all the quests in an area before focusing on moving to another town. You should focus on getting to Ashford 1st, then branch out depending on your class.
Theres a keymap that comes with your game, but just in case you "lost" it, heres a link to a list of keys.
here