The standard file manager on Windows 7 is Windows Explorer (NOT Internet Explorer).
The one that shows all your disk drives and the files and folders on them.
You can probably get to it using 'My Computer'.
While the pocket book is plugged in, it show up as an extra letter in the list under 'My Computer':
it will say something like (but NOT exactly) Pocket Book (E: )
You can use this to copy the book from the computer to the Pocket Book.
It sounds as if you aren't too familiar with comptuers; if you can find the pocket book but don't know how/what to copy,
post back again.
You may need to get help from a friend to show you.