Re-binding is definitely an advanced technique, and it will not matter until you get into high level raids or pvp. I would focus more on learning your abilities and being a conscientious groupmate. You can always change your keybinds around later. I played WoW for about 2 years before I unbound keyboard-turning and rebound my movement to ESDF. It sucked for about a week. Then I got used to it. And now it’s 6 years later, and my binds feel as natural as breathing. It can definitely wait.
Tip: Once you hit level 15, you can group for dungeons with 4 other random people (one tank, one healer, and 2 other damage-dealers). Press I–that’s a capital eye (i), not a lowercase ell (l)–to bring up the “looking for group” pane. As a rogue, you won’t be able to queue as a tank or healer. Rogues can only deal damage, so the queues can take a while–anywhere from 5 to 25 minutes on average. But also, there are a lot of people leveling monks right now. So maybe it’ll be quicker. You can and should continue questing while you’re in a dungeon queue. You just cannot queue for pvp while in a dungeon queue, it’s one or the other.
Oh yeah, you can queue for PVP battlegrounds beginning at level 10, too. Those don’t require any form of etiquette, really. Just activate stealth and sneak around, killing everything you can (try to focus on healers, their hands are usually glowing green or golden). And, although PVP is not the most efficient way to gain xp, battlegrounds are a lot of fun. They can be a decent way to level if you hate questing and dungeons and only enjoy PVP, which is true of a significant portion of WoW’s playerbase. There are two battlegrounds you can do right away, Warsong Gulch (aka WSG, capture the flag) and Arathi Basin (aka AB, control 5 bases). Rogues make decent flag-runners once they get Sprint, but they’re pretty vulnerable outside of stealth. You can be more valuable in WSG by sneaking around the enemy’s base and killing their flag carrier or healers. And in AB, you can sneak around and capture bases that the other team leaves unattended. It’s great fun, rogues are very tactical. Choose your battles, and run away if you have to.
As for group/loot etiquette, a loot window will pop up when a green or blue piece of gear drops. Blue gear is better than green gear is better than white gear is better than gray gear. Never roll “Need” (the little dice icon, on top) on something unless it is an immediate upgrade for you. Something with intellect or spirit on it is never an upgrade for you, not even if it’s blue. A need roll means you need and intend to use the item right now, so your roll gets prioritized over “Greed” (the little gold icon, on bottom) rolls. A need roll of 1 will beat a greed roll of 100. Most people roll greed on most things, and need only on the upgrade or two per dungeon they may encounter. Don’t “Pass” on anything, because you can sell some of those items for a decent amount of gold. When in doubt, default to greed. Or you can just ask the group, “Anyone mind if I need on that?” If it’s an upgrade for a rogue, nobody will care. If it’s not a rogue item, someone will usually speak up.
Something is generally an upgrade for you if 1) it has more agility than what you’re currently wearing (or raw attack power, which is sometimes a separate stat), and 2) it is leather or a weapon type that you can equip (1-handed daggers, fists, swords, maces, axes, maybe more?). You can’t ever use 2-handed weapons, and you should never use cloth. Never roll need on anything, gear or weapon, that has intellect or spirit or spellpower on it. Not even if it’s blue and you’re currently wearing a green. You’ll get called a ninja and may be kicked from groups if you need on stuff that isn’t a rogue upgrade, even if you’re replacing a gray with a blue.