how do i enter my account and password?
I turn on apple tv and it says that the account name or password is incorrect and to try again, but I can't go anywhere else to try again
Responses can only be as helpful as the relevant details provided and almost none where given here. The actual message would be a good place to start since from you description it is not possible to tell what you are trying to login to. WiFi network, iTunes, homesharing, iCloud, AirPlay....