Start with your left hand around your partner's right ankle, ensuring that they won't remove that foot from the equation right away. Cross grip your partner's right sleeve with your right hand. Meanwhile, your right foot can be used to maintain distance until you're ready to sweep. Just move your right foot behind your partner's left ankle, propping their foot so they can't step that back now either.

The mechanics of the sweep are simple and predictable: just pull forward with the hook and hand, making sure that your partner can't step back. Just push their hip back, and the sweep occurs. Following up on top can be tough if you don't maintain sleeve control, so keep this so that you can help pull yourself up on top. Once you get there, you have a relatively broken open guard to deal with, as your partner scrambles to recover some semblance of the type of guard they want to play.