Chris Baker of Lucky Gunner is an extremely well-trained shooter, and he puts together good videos. He put together this guide for running a pump shotgun hoping to provide good info for first-time gun owners due to the current panic, but it's good, all-round info for everyone.
How to Run a Pump Shotgun
He has another video on reload techniques:
How to Reload a Defensive Shotgun
How to Run a Pump Shotgun
He has another video on reload techniques:
How to Reload a Defensive Shotgun