If you bought an app from the Google Play store you have to Register to use your mail on the app that you purchased!
Once in the app you will have to put your registered email and then you will have access to the PDF Manuals of the software.
Buy 3 apps for the price of 2
Get them now for only $13,98
If you buy 2 apps you'll receive the other product of the trilogy (ESP, PET, TRAVEL) for free, you'll be receiving a code in your registered email
with the product code to activate it on the Google Play Store after you activate both products IN THE APP on your cell.