This is probably the simplest pass you can execute from a standing position. You grab both the ankles and throw them to the side. But there is more to it than just that.
I start with the throw by pass, using a bit of a juking motion to disorient and fake them out a bit, followed quickly by a knee on belly. We can then double throw by, anticipating our opponent quickly turning back into us and throwing the legs by a second time. This is more effective as you use their momentum against them.
In MMA, we can also add on overhand right which can be devastating from this position, making the pass even easier.