look at the rear of headlights from the engine room. Close to the section where the turn lights are there are the bulbs for the parking lights. There are 2 versions.
One with a plastic rod of about 10 cm. Front end has the bulb inside, other end has 2 pins to connect to the wire loom.
The other one is attached directly to the dip light on the upper half of the reflector.
Grab the thing from the back, push a bit towards front and turn a bit to the left. Then you can pull it out. If you cannot find it, just follow the cable to the headlights.
The plastic might brake, cause it got brittle over the years. Mine were broken 2 months ago into small pieces when I wanted to replace the bulbs.
By the way, that is also nicely described in the owners handbook.
Reverse light: do you have a manual or auto trans?
Anyway, could be the switch. But first I would check at the bulb if it gets power or not. Clean the contacts of the bulb.