how is early access going to work?

[Daralii]

This isnt 100% new classes will be available from the start of early access this is what happened in Heavensward and Stormblood the new classes required that you could get to the new zones for their class stories but im sure you can pick up the job quests in the ARR world.

It's already been stated at FanFest that the GNB trainer is in Gridania and the DNC trainer is in Limsa.