There usually are some players outside that have a crew for you to join.
But look for the people that shout "DMS" or "reg",
those are usually for YM, you're not ready for the rest yet.
One thing before you start though, I highly suggest you have these rings at CL 10.
2 - all buffs, if it's only 2 tell your leader before they assign buffs, I can't stress this hard enough. If it's all that would be fantastic.
Hack, slash and mantis, these three are the best 3 attacks you can have and are perfect for DMS.
Meat/shuriken/bump, Meat if you feel safer with that HP boost, shuri if you're a daredevil. Shuriken is also a great attack and has a debuff that will lower the targets accuracy, which is a nice bonus. Bump ONLY if you know how to handle it's knockback.
Fortune's favor/fitness/integrity, A passive will be great to gather more shorbs, and of course because of the stat boosts. Integ is 150% (I believe) better than fitness, but it was a one time thing. Don't have it? Too bad, you never will. Fortune's favor is great for boosting your luck, to get even more shorbs, it was only available during some easter events, events we will never have again. But don't be sad, you can still buy it on MP!
Shuri/Bump/Fortune's favor/fitness/integrity, For this one you can either take another attack (I suggest you put these before the passive because a passive works even when it's locked while an attack doesn't), or another passive.
OR
Adrenaline, you will only need to take this when the leader tells you to. R2-3-4 it on every monster that is being attacked, no need to do the whole room at once. R4 it on NF's and BD's and try to do it right away, if you don't have rage just R1 it.
And don't forget to listen and follow instructions, most people only want to help. There are some bad apples in there, if you encounter one there are both the leave and ignore button.