Noob player with no idea what is going on.

[Smitikus]

So I downloaded this game and started an account in mid 2015, played until level 15 and stopped.

I just came back and have no idea what is going on so I have some questions. I rolled a new character to start fresh with so this is coming from the perspective of a noob player (which I am.)

1. How should I be leveling? Do I ignore common quests and only do Story/Class quests while completing hunts?

2. I plan to tank on a Warrior, should I start as a Gladiator or Marauder? Or do I just get both Gladiator and Marauder both to 50 and go from there?

3. What hints or guides are there to show me how to get every class and job to 60? My goal is to have a single character that can do everything so this information might matter for an approach to that goal.

edit:

4. Can I change my World Group setting (to gain access to other servers)?