everytime i try to dismount i get a knot
I suggest opening the mount and swinging it around the back.
I suggest doing what he says in the video…
Are you rolling it onto that string closest to you and dropping the other strings?
Please give us more info so that we can help you!
When trying to land the dismount on that back string, it helps to turn your throwhand wrist towards yourself.
you could just try to pop it out like in the Bucket Mount or do a Ripcord like motion 
I was stuck on this for a while too. This video really helped.
Just pop it off of the string towards you (not over and strings just pop it off of the one it’s on) and drop everything. Easiest way.
You could drop your right finger and go into a green triangle then dismount from there. It’s what I did before I learned the dismount to trapeze.