To open your e-book on an iPad/iPhone, follow the steps below:
Install the Javelin reader free from iPad/iPhone AppStore
Download the e-book
Copy the e-book download link (from the email you have received) and paste it into the Safari 'address bar'. This will take you to the Dropbox page. Click on Direct Download twice, and the file will start downloading.
Then choose the option ‘Open With’ Javelin and it will open the e-book on Javelin directly.
Activate the e-book
It will ask you to enter an authorisation code the first time you open the e-book. Copy and paste the authorisation code (from the email you have received). You must have an internet connection at this point.
To open the e-book next time, open Javelin and touch the icon for the e-book file.