[like00111]

I bought a book online, not from any big retailers or anything. It is a book for studying questions.
What I want to do is be able to put it onto my kobo h2o, but the problem is that I got a weird file once downloading the book.
When I first downloaded the book I had to download 4 files and one of them was a .exe file that I had to use to enter the key for the book. After entering the key it activated the pdf file but instead of a normal pdf file it got saved as example.pdf.mmf
I cannot figure out how to add this book to calibre in order to add it to my kobo. Any help would be great.