borrowed book from the library

Hi everyone
I am very new at this and I hope I'm not asking a silly question here.
But here is my issue.
I borrowed a book from the library, and it's an EPUB format.
The book opened through Adobe Digital Library on my computer, and I can read it there just fine. I was hopping that I could transfer it to my kindle fire with the help of Calibre, but if it's something that can be done I cannot figure out a way to do it...
Can somebody help me?

Thanks a lot in advance!