The dryer is running and turning, but thre is no heat. We woudl like to fix it. Help 
First, I would pull the bottom panel off (#49 on this diagram), turn the dryer on and see if the igniter comes on. If the igniter glows but no flame in the burner, the usual (but not the only) suspects are the gas valve coils.
Replacing the coils is pretty simple. Unplug the power to the dryer first. It’s also a very good idea to turn the gas off at the shut off valve behind the dryer. You already have the bottom panel removed, remove the cover that sits on top of the coils, change out the coils one at a time, replace the cover and try the dryer again.
Hope this helps.