What kind of editing is this? I was just doing whatever popped up in my mind and did this. I want to watch tutorials or maybe read theory books but idk how to name this. Is there a specific name? How do i get better at this?

What kind of editing is this? I was just doing whatever popped up in my mind and did this. I want to watch tutorials or maybe read theory books but idk how to name this. Is there a specific name? How do i get better at this?