To be certain, you should:
1. Consult your owner's manual: This is the best place to start. It should have a diagram showing the location of fuses and relays.
2. Check online forums: Search for "2000 Pontiac Grand Am GT turn signal flasher location" on forums like GM-Trucks.com or similar automotive sites. Someone may have already posted pictures or detailed instructions.
3. Look at the fuse box diagram: The fuse box cover often has a diagram indicating the location of relays.
Don't just blindly start pulling things apart. If you're not comfortable working on your car's electrical system, it's best to take it to a mechanic.