Video 1 is illegal techniques that we don't allow in rolling in our classes (heel hooks, knee bars, neck cranks).
Video 2 is about the combat base and knee slide guard pass.
Video 3 is about the scissor sweep.
There are very few techniques in jiu-jitsu that I feel I own. It's definitely the sweep I've done the most over the last twelve-plus years.
So here's an explanation of how I do it:
1) Start in closed guard. Right hand (fingers) in the collar, left hand gripping his right sleeve. Important: hold at the bottom of the sleeve right by the wrist, and hold it tight enough that he can't move his hand at all. I prefer the "joystick" grip.
2) Post your right foot on the floor and hip out slightly to that side - just enough so you can slide your right knee up under his arm to his sternum. Your right foot should post on his hip now. Your left foot should go to his right hip.
3) To easily sweep someone with the scissor sweep, you need to get them off their base first. To do this, push them with your knee. They will most likely push back. You may have to do this a few times.
4) When they push too much, they come off their base. At this moment, do three things: 1) sweep them over your left foot by scraping it along the floor. DON'T LET IT COME OFF THE GROUND! 2) knock them off their base by "kicking" them with that right shin that's across their body. 3) Pull with both arms to further take them off their base.
5) Follow up to mount position. Immediately arm bar or cross-choke them.
6) If they base way out because they know what you're trying to do, shrimp out further and put your left foot on their knee cap at floor level. NOTE: when you shrimp, don't shrimp away from them... shrimp backwards, to your right. Be completely on your left hip. You shrimp to the side so that when you "stomp" out his right knee, it pushes him into a split and he tips forward.
7) Still kick with your right and pull with your arms. Follow up the same as above.
Maybe one day I'll post a public youtube video on the scissor sweep. Honestly, the only reason I'm hesitant is because I know that every teacher teaches this one differently (Marcio Stambowsky's scissor sweep is completely different than the one I just described) and I'm not in the mood to have 500 comments like:
"dood im not impressed, this is liek totaly wrong, my prof. teachez it diffrent."
"i did a seminar wit one of them gracies once and they said its different so u suck."
"Ur head is 2 shiny."
But yeah, let me know if you have questions on my version. When you land it with the correct timing, it's decisive and you're opponent goes right over, so angry that he just got swept so cleanly. It's worth working on.