Hello all! Loving ff14 since i restarted huge improvements since beta and early launch.

So as a newbie with some experince playing ffxi i have a few questions regarding classes and grand companys as well as a few other small things.

Question 1! as someone that loves melee classes tanks or dd which class would be best to rank up first, or which classes are more subjob related like war and nin where in ffxi?

Question 2! I know you unlock grand companys at level 25 ish but my confusion comes from i can still do all three? THerefore would it be better to grind the other two ones i dont want to get the lower rank gear and items or can i change companys later like you could with city states in ffxi?

Question 3! Last one dont wanna make this too long ^_~!

Ive noticed they implimented things that look like dungeons in WoW how do these work?!

Thanks in advance!