Hi, im a first time map maker and am barely grasping the radiant black tool. I have some rudimentary brushes down n such, but i want to add details like models and stuff. Im not sure how to add models, add perks, or set up barricades that have zombie spawns. Any sort of help would be appreciated! 
    Thanks, Alacrity

Go on youtube and look up blackjackjonny.
He goes through all the basics in the world at war radiant.  As it's very similar it will familiarise you with radiant.
When you've done all his tutorials, move on to Wakka, JDBird and Zeroy's tutorials for Radiant Black.

Good luck

That's an easy one.
You haven't built the main files using the launcher...and if you did, somethings missing now.

Backup whatever you've made, go to the launcher (the BO3 MOD TOOLS ICON), go to file > new and click "new map".

Type whatever name the map is going to be mp_mapname for a multiplayer map or zm_mapname for a zombie map.

You will see that a popup appears saying it's made a heap of files.

Copy your map into the map_source directory and overwrite the one you just created with the launcher.

Providing all the models are working, the map should compile fine.
Hope this helps