The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From School Fuel:
School Fuel is a Mobile Learning Platform that allows teachers and school leaders to connect with students in class and on the go. School Fuel provides customized app and resource libraries aligned to Common Core Standards helping schools deliver the right apps to the right students at the right time - on any device.