Q: I am in my login screen, I do not remember my administrator password, and I want to reset the password. What do I do?

I have a macbook air and I am stuck in the login menu.  I do not remember the main account's password.  I am fine with resetting it but in order to do that, I know you have to turn it off.  When I press the "shut down" icon, it says I have to enter the administrator name and password and then i can shut it down.  Well yeah, I cannot remember my administrator name or password.. What the **** do I do??