A video course I am following shows the Layers panel as below:
When I duplicate the course instructions, my Layers panel shows the following:
What would be causing the different display?
I am using the Photoshop CC 20.0.1 on Windows 10 x64.
The white boxes in the lower screenshot are Layer Masks. See this tutorial from Adobe.
A new adjustment layer comes with a white (empty) layer mask. It doesn't do anything as long as it's pure white.
You can delete the masks by dragging and dropping them on the trash can. The person who made the tutorial must have deleted the masks to "tidy up".