I went to Azala town for the main quest talked to everyone. Even recruited the mage girl. Can’t figure out what to do next. Do I have to beat the cult to progress cause I keep losing the first fight immediately and I there are no lower level enemies to grind. Am I missing something? Also I can’t access anywhere but the starting towns can’t go into under dark or forest to the right of map. 

Those are restricted area for the moment, as for what to do after your recruited the Priest you must buy a staff for her to be able to use her skills. without the staff you can't use the spells... you can buy one relatively cheaply at the item shop in Azala town and it should trigger the next event.