How do you change signal light bulbs on the front on a 2002 Chevy Venture?

There are two plastic wing nuts and one bolt that hold both light assemblies in place (the headlight and turn signal are in separate assemblies, but are wedged in there together).

Open the hood and remove the three wing nuts/bolt. Lift the headlight assembly off the bolts and the turn signal assembly will pull forward then out to the side. Be careful of the two tabs that lock the rear of the turn signal assembly into the fender.

(On my 2000 it is only necessary to remove the bolt that holds the turn signal assembly in place if you don't need to replace the headlamp. The assembly may then be removed by pulling forward on it to disengage the tabs. It is also easier to get it back into place if the headlamp assembly is still bolted in--align the tab and guide in the back and push the assembly back to engage the tabs. Then replace the bolt.)

There is only one bulb for the turn signal. Rotate the base of it counter clockwise and it will come free. The bulb is a push/pull type base, so it doesn't need to be screwed in or out. Reverse the process to put the new one in and reassemble.