Establish same-side sleeve grip and underhook belt grip:
(your right hand grabs their left sleeve. Your left hand under hooks and grabs their belt.)

Try to hit the sweep by lifting with the hook (left leg with these grips) as you try to put your ear on the matt and kick your other leg under your hooking leg, turning your hips sideways.

They post with the leg to stop the sweep:
trap the leg with your arm, grab your lapel to trap.
push on their hip with your top leg.
keep your inside hook, point your knee up, and keep it tight on them so your shin blocks them from leaning in.

if they lean in:
grab their lapel with your free hand.
sit up and push with your hook shin to get the sweep over their trapped leg.

if they turn away and try to stand:
stand up with them as you gable grip behind their knee.
pull them backwards, then drive forward to get the sweep and proceed to pass.

if they post out to the side with their arms:
try to take the back
small bump and pass the trapped leg over your head while you grip the inside of this knee at the gi with your free hand. keep this grip.
take your top foot off of their hip and set a hook (this hook is like a butterfly hook but they have their back partially turned.)
now grab their belt with your free hand and pull your other leg under them to set a second hook.
now pull them toward you (you’re behind them with two butterfly hooks) and take the back.