Normal node in Substance Designer

I decided to make my node normal.
You may also want to do it yourself.
Then this is for you:
I tried to write down all the technical explanations.
I attached a screen in good resolution. And also posted an SBS file on the comrade
https://androfroll.gumroad.com/l/lcvgbl
Perhaps it will be interesting to someone, for a deep understanding of what normals are