I tried Zork 1. I got stuck immediately. I saw a house, went to it, read what was in the mailbox, but couldn't open the door. Now what? I never played the origi

I tried Zork 1. I got stuck immediately. I saw a house, went to it, read what was in the mailbox, but couldn't open the door. Now what? I never played the original Zork but if this was D&D there would be a little more information to go off then just "you see a house and there is nothing you can do there".