How do I get the fan belt inside of the Dryer?

These do not have a "fan belt" rather the fan is attached directly to the motor. however the "drum belt" is another matter...First unplug the unit from the wall.

This is a process that takes a little practice, so if you're not mechanically inclined, it'll take some, how should I put it...patience. An experienced tech. like myself can do this in roughly 5 mins. I digress.

...after unplugging the unit from the wall, lets do this step by step. (or follow link attached) http:////www.applianceaid.com/ge-dryers.html

1) open the dryer door.
2) remove the screws at the top of the drum opening that hold the top down secure. (get a magnetic screw driver...it will be handy later, especially in step 5)
Now you should be able to feel the top free to lift up.
3) lift the top up while gently pulling it towards you. It should come off completely and you'll see the drum and belt (if the belt hasn't fallen into the bottom after breaking).
4) standing over the unit with the top removed, look down to the left and the right of the inside front and you should see a single screw on each side.
5) while applying slight pressure to the front with a knee or leaning into it, remove those screws.
Once these screws are removed, the front panel is almost ready to come off, but wait...WIRES.
6) To your left (when facing the unit) just below the door opening, there will be the door switch. remove those wires (remember or mark there location) as well as the two for the drum light at the top of the door opening...if applicable. now you should be able to move the front away to the side freely.
7) now the tricky part. if the belt is broke, you should be able to reach in and remove it. place the new belt around the drum with the "v grooves" facing the drum. once the belt is around the drum, you'll have to get both hands in there, place it over the idler pulley/belt tensioner. (you're almost there) once you've done that, grab the belt from under the "idler" (careful to keep it contacting the wheel on the idler) and pull the belt back towards the motor pulley and wrapping it around the pulley so as the "v grooves" in the belt align with the grooves in the motor pulley. It should be like an "S" shape when installed.
If you've managed to do that without anyone visually showing you how...well done. It's tough even when trained at first.

putting it back together is only a matter of reverse order of disassembly, althought the top can be tricky to line up at the console. (you may find it easier to loosen the screws on the console to slide the top into the grooves at the back support).

hope that helps. It's a tough one to explain, especially the looping of the belt around the idler.

good luck.