How is this not checkmate?

What about it?

I know absolutely nothing about chess, but I'm doing a puzzle and i moved rook from F8 to F1 and it says I failed, am I missing something obvious here?

My first accidental checkmate

What about it?

(I was the white pieces)

Idk

What about it?

I just started playing chess last night and I'm confused on how this is a stalemate, can anyone help me understand?

My first accidental checkmate

What about it?

(I was the white pieces)

This is not a brilliant move but it’s still cool.

Angry Pawn

Happy to find this checkmate

Can you see the beautiful sequence that I missed in this game? Black to play.

Why is this brilliant?

why is it a brilliant move?

I got accused of using Stock Fish, am I going to get banned even though I didn't use Stock Fish?