Hello. I have to hire a Coach and I want to know does the money come out from my salary cap?? If not then where does the new Coach salary come from??

No, it comes from a separate money pool. I believe it comes from the fan attendance stat on your team home page.

Fan attendance/ ticket sales.

The money pool can be increase or decrease from season to season according to attendance / team success.

You can see the money available on the top of the page when you try to sign a new contract with a coach