Position the top so that it down, but the tonneau cover is still open.
Turn off the key.
You now have about 10 minutes to dive in and change the bulb, they are easy to see, not so easy to reach.
( you can place a brace between the cover and the rear bulkhead to keep the cover from dropping on you when the pump releases it's pressure )

Some find it easier to just remove the 3 10 mm nuts, unplug the connector and remove the light assembly to replace the bulbs.
Not a bad idea to replace all 3 bulbs on both sides and be done with it.