First of all, thank you very much for your amazing comment.
You can think of logical gates if you know about them. The middle node is an NOR, which means that the output is on when all inputs are off.
The two nodes at the sides are NOTs, they just invert the input.
We keep in mind to intoduce such mechanics a little bit more intuitively and understandable next time!
If you like to, maybe give it another try with the explanation aboth. There is a lot you did not even explore yet!