Default Bricked? Maybe... ?

OK let me start off by saying I have really no idea what I am doing. lol. I have rooted and done custom roms in the past with older phones. I was trying to upgrade my Nexus (JDQ39- Verizon) to 4.4.2 Kitkat from 4.2.2. Well when I loaded the TWRP (v2.6.3.1) I believe to manage to delete all existing files and roms off of the device. So now I get the google screen with the unlocked icon.

Now I can get into the TWRP loader up. Windows will recongize the phone but will not give me any icons to copy the new rom over to be installed. I try to mount to my computer but says E: Unable to mount '/'

So I have no idea where to go from here.. lol.

Thanks for the help.