How do I install a wall mount lighting fixture when there are 2 black 2 white and 2 ground wires from the wall
It appears likely that one cable, with a black, white and ground, is the feed (source of power), and the other is a pass through to the next fixture or outlet.

In that case, you would simply join your fixtures wires to the existing bundles, matching colors.

This assumes that switching is already in place, or the fixture has internal switches.