This is where you step directly into the court with your left foot in the lead, and your toe pointing towards your opponent.
It is important you roll your front foot from the heel to the toe in order to keep your momentum moving that direction (through the ball).
You keep your shoulder turn quick, the racquet goes straight down to just below the ball, and you rotate your body as you hit the ball. After you hit, your back foot should swing right around your body to end up in front.
There should be no wrist involved. There should be almost no arm movement involved. It’s all legs and body rotation.
The best drill for the shot is shadows without a ball, practicing technique. Then you can practice dropping a ball in front of you and stepping into it with full body rotation.