Sorry it's too late to get 2018 into your existing 2019 return. You can only transfer it into a new blank return like you just did. What do you need from it? Either forget about it or you need to re enter all your 2019 info into this new return. You can manually enter any 2018 info it needs into 2019 as you fill out 2019.
Do not save this new return unless you save it with a different name or it will probably overwrite your existing real return. Go up to File-Save As to give it a name you can tell apart.
