2 PEOPLE USING THIS TURBO TAX, HOW DO I START NEW RETURN?

Did you pay for a desktop version? If so, follow the directions here. After installation and to start a new or second return, go to the File menu and select 'New Tax Return' to begin.

Did you buy the CD?  You can download the program if you don't have a CD drive.  But be careful not to get stuck in the Online web version.  That's been happening.  Have you used the Desktop program in prior years?  

Is there a black menu bar on the left side with the menu items, like Home, Tools,  Federal, State, File etc. That is Online.

OR if you want to use the Online version,  Online is only good for one return per account so you have to pay separately for each return.  But you can use the same email address for 5 accounts. Online is only good for 1 return per account. So don't use your account or you will overwrite your return.

Start another Online return here. Sign up and start a new account.
https://turbotax.intuit.com/personal-taxes/online