Back again, no luck!

I'm so annoyed, I bought the first e-book and downloaded to laptop, then transferred file, then wasn't able to access due to password problem. I bought another a little while ago, this time through my 770 tablet, and for whatever reason, I can't access the download screen. It says to click on the download button below, but there isn't one.

Is there anything I need to do? I'm downloading the adobe reader format - I'm not technically savvy, so I am finding this really frustrating. I started on this project over 24 hours ago and I still haven't been able to download an e-book. Is there any site more user friendly that I should try?

Any help, muchly appreciated, ta, Cathryn