Third Party Designee - how to designate IRS and CA?

How do I designate a Third Party Designee for both IRS and CA? I am using desktop TurboTax Deluxe on a Mac. I am unable to change the checkbox in Forms View from No to Yes. I am unable to type in any information in this section such as the Designee's name and phone number. I did not see where I can input this information going through the Turbo Tax Easy Step Process. I've done the final review and am ready to file except for this Third Party Designee issue.