The tripod sweep is a basic buy very effective sweep from open guard. It's important to set up the grips correctly, place one foot on the hip, and the other just behind the achilles of your opponent. Once everything is set up correctly, create a push & pull motion to sweep your opponent out of balance, and as they fall backward, perform a minimised version of the technical stand-up to finish on a strong passing position.
On the advanced variation, your opponent moves their feet around so you need to adjust your technique. In this case you are going to switch legs and the feet that was controlling their achilles moves to your opponent's hip, while the foot that was controlling the hip, moves down to sweet behind your opponent's heel. In order to make this adjustment you'll need to change your angle and positioning.
Finally, control your opponent's remaining foot with your free hand and perform the push & pull motion. The way your opponent falls and the way your legs are positioned is ideal to move into a knee on belly control Pay attention to the details as Sensei Douglas Santos from DS Team Jiu Jitsu academy breaks down the technique.
If you want to train at DS Team Jiu Jitsu in Auckland, New Zealand, find out more here: https://www.dsteamjiujitsu.co.nz