Problem/Bug Command Block Help

Hey guys, I've been coding a plugin and I am adding custom blocks, entities, etc. And I looked at the video, copied one of the mechanics he did and I put it in my computer, when I uploaded it through a command block in minecraft I see that it isn't working. In the Command Output in the command block it usually says Object Successfully summoned or the usual help unknown command thing.

Also, how would I import this to my code to make it look a little nicer?

Thanks!

Links: https://mrgarretto.com/model/ - The Model maker I used