Our site is set up to automatically populate that dropdown box with the appropriate files for your OS. As such, our site requires a certain amount of access to your computer to be able to determine your OS. If you have tough security features on your browser that prevent such things as cookies, you may need to disable them for a moment, at least for our site, to allow the site to work properly.
Atlernately, you may want to download the files onto your iPad and then move them to a cloud-based storage which you can also access from your computer. You should just need the one driver for your OS plus the apps corresponding to your OS. While the apps don't need to have the driver present at the time of installation, they will require access to the printer in order to run properly. Thus, we recommend installing the driver first to ensure that the apps work right after installation.
Hope this helps!
