You can order and download direct to iPad or another mobile device (or mix and match, for that matter—you're not limited to the single device you use to purchase). You don't need a computer or laptop to transfer files.
Once you place an order via your iPad, you'll get a set of download links. You can download the full package to your iPad, but better yet, just download the file needed for the app you want to use (reader, video player or audio app), so you won't use as much space on your device.
However, Apple doesn't like us freely downloading material to an iPad. Depending on which apps you have installed, there are occasionally problems downloading video to iPad. You may find video streaming a better option.