If the blower works, (blowing air at the back) that means the motor works! Try it on "No Heat" so the elements don't come on.
The motor drives the blower directly on one end and the drum with a belt that goes around it on the other end. Some dryers have a belt safety switch but I don't think any 1-18 dryer has one. If the dryer hasn't been used much recently, it's very possible that the belt was dry and it didn't last long when you tried it. When it tumbled, was it noisy? These dryers often are.
When I got mine, I replaced the belt as it was about to fail. I also had to replace the drum rollers. A few years ago, while I was using the dryer, I noticed it made an unusual noise, I opened the door and that strange noise kept going for a few seconds after the motor had stopped. I figured there was an issue with the blower and there was one indeed! The plastic blower wheel had snapped on the motor shaft so it would turn slowly and vibrate when the motor was running and it would keep spinning on the shaft after I stopped the motor (by opening the door).
I replaced it with a Maytag blower which is about 1/2" smaller in diameter but it still works. I don't have a long vent so that's not an issue but I did find the original NLA Frigidaire blower wheel soon after so I have a spare one now!
Since I think no one else bothered to make a video of their 1-18 dryer, I made one with mine recently!
For those who hate these dryers, here's the proof that it can tumble and not being that noisy! (it's still far from being as silent as a Maytag HOH or even as an older Frigidaire dryer).