You can do this!!!

Take off the back lower panel and look inside. If you see the belt broken and on the floor, it is easy to replace it.

GE dryers usually have screws in the upper door frame that come out to let the top come off or swing back, but yours made be so old that if those screws are not there, you release the top by inserting a screw driver in the gap between the top and front near the edges. The top now flips up or off, you take off the front panel, put on the new belt, loop it around the tensioner the way it is shown in the Sticky on this page above and put things back together.

Make sure you clean out the dryer while you have it apart. A good idea is to remove the drum to do this.