Hello Elmo,
The digital delivery method means the file is downloadable from your account after purchase, rather than being delivered via mail on a CD. Years ago, many flight sim products had to be delivered by mail on a CD, but nowadays everything is digital.
When you purchase from SimMarket, you'll want to go to "Your Downloads" under your account. On the downloads page, there should be a link to the file to download, which should be TBPB_1.1_MSFS.zip. Click the link to download the file. When it completes, you'll then open the .zip file and run the .exe installer within it. That will start the installer program. The installer program will ask for the location of your MSFS community folder, which it will need to properly install the files. Let me know if you need assistance in locating your MSFS community folder.