Tail lights went out fuses and bulbs are all good?

Is it the parking lamps in the rear only? Or are the turn signal or brake lights out as well?
Different problems depending on which lights.

If it is only the parking lamps there is a fuse and relay in the left rear fuse box behind the wheel well that should be checked. The fuse is #6 a ten amp. The relay is #27 park lamp.
If there is power at the fuse put your finger on the relay and have someone turn the lights on. If it clicks but no lights, try replacing the relay. If the relay does not click the issue is in the wiring or the body control module and would require further testing. It is not hard testing but you would need to buy a test light.

Depends on where you buy one. A super deluxe model might run $30.00
Something like an ATD 5513 (which is all you really need for a lot of testing) runs around the $10.00 range.
Just a few of the tests you can use one for.
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Yes.

Tom, could you ask this as a new question and provide details of the vehicle you are asking about?