Help! How do I fix the hole in the wall?

[Sara Tummen Mitt i Handen]

Hi,
I have a hole in the wall that I would like to repair. But I don't know what the material in the wall is. Is it plaster? I absolutely know nothing about this kind of thing but it would be fun to learn to fix it myself. I've attached a picture and a video. Any tips are warmly welcome!

Thank you so much!

 

[Tiger79]

Common spackel.