When you are in 2019, you click on start a new return. Then it will bring up all the tax returns from the prior year. Once you select the one you want, it will bring all the appropriate information current into the 2019 tax return.

No, you do not.

All you need to do is sign in with the same user ID you used last year and we'll transfer your information over.

See this TurboTax Help.  See also here.