Insert Wooden Shims into Gaps

What happens here

The video begins with the man inserting small wooden shims into any visible gaps between the newly installed baseboard and the adjacent wall or existing door trim. He uses his hands and then the butt end of a utility knife to gently tap them into place, ensuring a snug and tight fit, especially around corners and alongside the pet door frame.

Goal: Create a tight fit and eliminate gaps between the baseboard and the wall/trim.