basically you should do it step by step in this order:
1. get your embelem(s) and grommets
2. to remove emblem slip something like an old id card in between the emblem and body then put a cloth under it just to make sure u dont scratch the paint
3. then stick a flathead screwdriver in to pop it off be sure to slide it around to make it stick out then pull it off <if you dont care about the emblem>
4. you'll then notice that the grommets stayed either on the emblem or on the hood/trunk so to pull it off the hood/trunk just get a pair of needlenose pliers and pluck it off
5. then clean the area
6. push the new grommets in place
7. push the new emblem in and there you go
almost forgot, i love my girlfriend