I have a disk version of Turbo Tax Home and Business. How do I start a second return?

With the TurboTax software started, click on the File menu at the top left of the desktop program screen.  Click on New Tax Return.

I have started my return and can not figure how to sign out and save my file. I have read other answers that say to click on my account at top right. I do not see that. I am using a disk version on an iMac. I have used Turbo Tax for years. but it looks completely different this year. 

I think the Mac program is the same as last year.  And Mac automatically saves.  You can go up to the very top bar File-Save or  Duplicate.