The safest way is to remove the bumper cover completely and work from the back so you can see exactly where the clips are and poke at the clips in the right spot. But it should just pop out by prying in the right spots.
Place painter's tape around the outer edges of the grills. Insert your fingers or trim tool into the outer top hole/vent pressing inwards when you feel the clip. As the top clip releases itself the two others on the outside of the grills should follow. When you remove the grill's outer portion, be cognizant of the tabs so they don't scratch the bumper or anything else. (This is why I recommend painter's tape) Once the outer portion is removed you'll see a push clip on the lower inside you'll need to move with a pry tool or flat head screwdriver. After removing the push clip, the whole grill will easily come out. To re-install simply backtrack to the removal process. Honesty, the hardest part is finding the best angle to press the tabs. Overall, it's a VERY easy process, it took me maybe 15 minutes to swap out both fog lights.