Looking for more advice about new players!Follow

What World are you on? If you can find someone in-game many of your problem can be solved very quickly. However I know how hard it is to sometimes get chatting with people.

To change jobs: You change weapon in your main hand. So if you want to be a Gladiator then change to a weathered Gladius. In order to do this you will need to buy one first! Try the Zam data base to find out where.
Being a crafter is the same as changing jobs, just buy a tool and swap it in your main hand.
Levequests - check your journal in your Menu when you have taken the leveqiest. It will tell you which camp to go to. When you get to the camp, go near the aetherlyte and open menu, you will get the option to start the leve. The goal/target again is explained in your journal and your minimap/map shows your targets. Go kill whatever it says and when you have comepleted you automatically finish and a temporary aetherlyte gate appears. Open menu and select it and you will get your reward and can choose to be transported back to the main crystal.
Gil is easy in this game. You receive it from levequests and every mob you kill drops stuff. You can either sell these to an NPC or put stuff up in the market wards.