Etryian Odyssey IV...Mapping and other questions

I'm used to the Auto mapping in strange Joruney, and apparently thats not a default type of thing in Etryian Odyssey?

My main question is how does the mapping work exactly? Do i have to just like, mark spots and when ive moved to a different area of the dungeon the map is completely gone say for those marked spots or something?

If so that seems a little..i dunno. seems like dungeons would take way longer. 

I love strange journey but I was wanting to try out Etryian Odyssey IV, seems really cool but I just dunno how that stuff works still. Thanks.

Oh also, About classes, u just pick out of all the ones available? do u unlock higher tier classes?

Might have better luck with a question like that at gamefaqs. The genre forums here are mostly very low in activity.