Band-in-a-Box is available for Windows and MacOS, your iPad uses iOS. It can't run Mac software, only iOS apps.
That being said, there is a free Band-in-a-Box iOS app available through the iTunes store that you can use. It's not a mobile version of Band-in-a-Box though, it's a companion to the Windows or Mac version.
You can find instructions for its use here: https://www.pgmusic.com/support.iphone.htm