where on the website can i file my sons return. it keeps going back to mine.

You need to create a NEW TurboTax account for your son.  You can only prepare and file one return per account.  Lot out and then create a new account.  

you can not use your account to do your son's return online. a separate account is need for each taxpayer with a unique user ID. The e-mail account used can be the same as yours.

a second return done in an online account will permanently delete the previous return.