Just simply do all things on the plane and after apply bend modifier, this way you will avoid lot of pain becoz it is easier to work on planar surfaces, hope you will understand it.
try to make the video without useless klicking back and forth on vertexes without explaining what you are doing. maybe try record like 4 or 5 times and you should have everything perfectly in your hand so you dont have to do so much ctrl z stuff. i was lost in 5 minutes what are you doing. it looks like you dont know how or what to do. please take this for constructive criticism. i wish you good luck in next videos ;)