My Kenmore 80 series gas dryer will turn on but won't spin

Hi, Sounds like the belt broke.
UNPLUG the dryer. This model you need to remove the two screws under the lint screen. Now use a flat blade screw drive and insert it in the gap between the top and the front panel and pry the top up. Now locate and remove the screws on the inside of the front panel in upper corners. The front should lift off.
There should be instructions that came with the belt. I will try and explain how this goes on. The idler pulley fits in a slot right in front of the motor. Put the belt over the drum with ribs touching drum. Now, thread the belt through the idler pulley wheel and bracket and set the belt on the motor pulley. The ribs should rest in the grooves on the motor pulley.
I hope this helps you. If I can assist you further, please let me know. Please rate me performance so that others as well as myself will know how I am doing.

Thanks
Vic