Custom validation where string does not start with a specific letter

I’m using your sample found here: but am not sure how to modify it. Can you assist?

Rather than just checking to see if a field value == 86, how would I change it to see if a field value does not start with the letter “H” or does not contain the string “none”

The field i’m validating should always be H followed by 5 random numbers or the word none. I want to exclude all over values.

How would I change the sample to do this?