No, you use the post pounder as a fulcrum. Lean it against the post, snagged under a tooth, then pull the top of the post toward the pounder. That forces the post upward. Repeat as needed on subsequent teeth to ratchet the post up out of the ground.

Here's another video showing the same thing:

https://youtube.com/shorts/HCqpRfj1KBs

Ingenious.