Storage Space Issue for AT&T Cameox

I'd move all of the media files (music, videos, and photos) to the SD card (using the same or similar folder structure).

Also, if the phone supports Adoptable Storage (i.e., the ability to format the card as Internal Storage), that would give you more space to install apps. To figure out if the phone supports this feature, see if it gives you the option to format an SD card as Internal Storage vs Portable Storage.