Trying to enter another fed and state income tax returns for someone else how do I do that?

When you go to the screen where you usually log in for the other account, look toward the bottom and there is a link that says:  New to Intuit? Create an account  You can click the link in this answer or on the link from the sign-in page.  You may make the same email the contact for both accounts, but be sure to save the logins and passwords for yourself. You might get a TurboTax security email from us to alert you that the email was used on two accounts.