As you can see in the first post of my tutorial topic i have a list of comming soon stuff wich includes your request
-skybox
-minimap
-ingame map
But as i am quite busy with my school right now and i recently had nearly no spare time the last weeks ,you will have to wait some time until i can come back for modelediting
Sorry i can't do more than my best.
The only thing i now can do is to let you find it out on your own.
Use the
http://wowdev.wiki/index.php?title=DBC overview and try to understand how the world maps are working. I don't know that right now too and i never did create a custom map , but i will.
Just give me time