After you file

Ok ...  so you started the 2019 program in the Deluxe version ... if so you can still get just the AGI without paying anything ... on the home screen scroll down ...

If you need to get a copy of the 2018 return in whole and you are going to use the 2019 deluxe version then simply pay the fee now to access the prior year return.   Otherwise you need to clear the return and start over in the FREE version so you can register the account to get access to the prior year info.  If you need more help then contact TT support for one on one assistance.