While we don't have a video on how to change the tire, I can certainly provide a solid instructional outline for you to follow:
First, you want to make sure the bicycle is powered off.
Then - unplug the motor cable on the right hand side of the bicycle near the motor. There may be a zip tie holding this wire to the bike frame - you want to cut these zip ties before removing the rear wheel.
Then, you want to remove the gates belt drive - you can pull the bottom of the belt towards you, and pedal the crank backwards - this will pop the belt off of the front sprocket.
Then, loosen both axle nuts on either side of the wheel.
For easier removal, I recommend removing the brake caliper on the left hand side, as well as removing the two piece of hardware that hold the struts of the rear fender in place. It's possible to remove the rear wheel without removing the caliper - but its a big time saver at the end of the day, because clearance is exceptionally tight.
Now you can slide the rear wheel completely out of the frame in order to replace your tube. Don't forget to check the inside of the tire, and the rim itself for anything that could cause a flat.
Now you can reinstall the wheel, push it all the way forward, and pop the drive belt back into place. Make sure the wheel is straight, and tighten the axle hardware on both sides.
Now you can reinstall the brake caliper, and reattach the fender - and you're good to go!
Let me know if this is clear - or if we can assist with anything else.