Hello there, @jlclark137.
I'd be glad to help share information about installing QuickBooks Desktop (QBDT) and updating your company file.
Once done installing your QuickBooks Pro 2019, you can just restore your 2012 company file to your QuickBooks Pro 2019 so you can continue using the file. Before restoring the file, you must back up your 2012 company file first.
To create a local backup of your file:
On the other hand, to restore a backup of your company file:
To learn more and for the detailed instructions, you may check these articles:
On the other hand, if you need further assistance with the process, you can always get in touch with our QBDT Support Team. For the support's contact information, you may check it here: Contact the QuickBooks Desktop Customer Support Team.
As always, please don't hesitate to add a post/comment below if you have any other QuickBooks concerns. I'll be always here to help you however I can.