Turn signals inside are steady and don't blink. Exterior lights don't turn on at all in rear. Front signals turn on but stay on and don't blink.

This ether sounds like you have bulbs burnt out in the rear, a fuse blowen, or a bad flasher

first check the fuses to see if any are blowen (usually a blowen fuse will lead to this issue)

then replace the bulbs that are not working

replace the signal light flasher (this is usually found in the fuse box in the cabin of the car or mounted to the steering colum)

i hope this helps ^-^