I suggest opening the file with either Apple iBooks or the Adobe Acrobat app for the best experience on mobile.
For iPhone users please see this simple step by step guide below to save the book to Apple iBooks. The same can be done for Adobe Acrobat on Android. Follow the images from left to right across the top row first, then the bottom row.
Follow the instructions marked in red to save the file to Apple iBooks.
For PC & laptop users: Download file and save it somewhere you will be easily able to find it.