For iPad or iPhone (iOS)
First download the free app 'Apple Books' or 'Books' app from the iTunes App Store. Then download the e-book and open it with this app. Afterwards the book will automatically be stored in the library of the app, where you can open and read the e-book.

For Android tablet or Android smartphone
First download the free app Google Play Books from the Google Play Store. Then download the e-book and upload it to the Google Play Store (click on the completed download in your notifications). Afterwards it will automatically be stored in the library of your Google Play Books app, where you can open and read the e-book.

For pc, Mac or Windows tablet
First you need to install Adobe Digital Editions. Click this link. Then you can download the e-book. Save the e-book on your pc, Mac or tablet. You can then open and read it with Adobe Digital Editions.

For your e-reader
Most e-readers are suitable for reading an e-book in ePub format. You don’t need to install any additional software.

Other (In addition to the above mentioned options)
An e-book in the standard ePub format can be read on any reading device and any reading application that supports ePub.