The Mexico international has settled quickly since his arrival from Chivas.
Hernandez told The Sun: "United have enormous options up front but Alex Ferguson has given me chances and I'm grateful for that.
"He is a coach with very clear ideas. From the first day he spoke with me and explained what he wanted.
"He insisted there was no need for me to feel anxious or nervous. I think I am fulfilling what he wants.
"I am a very open person myself and am trying to be friendly with everyone. But because of the language situation, I have more contact with Anderson and Nani.
"The biggest thing for me has been the change of food and the climate. I didn't realise it would be so cold here."