Thanks for posting the Community space, @ValarieA.
Before setting up the desktop application, make sure you meet the necessary system requirements. This will ensure the application is compatible with your setup and will help avoid problems when installing it.
Once done, choose your product and version, and click the Download button on the Downloads & Updates page. Then follow the steps in this article to successfully install QuickBooks desktop: Download QuickBooks Desktop. You can also follow the direction stated in the QuickBooks Desktop 2021 on how to connect the app to the program.