I don’t have any Apple devices capable of reading on, but for those who usually buy their books from the iBooks store, I’m told that sideloading your free .epub file can be done one of two ways.

1. Email the file to yourself, open the email in your mail app, tap on the attachment, at which point your device will ask you if you want to open the book in iBooks, at which point it will copy the book into iBooks and then open it for you.

2. The other option is to connect your iPad/iPhone to your computer, open up iTunes (if it isn’t open already), go to the ‘Books’ section of your library and then drag your .epub file into that window. Alternatively, you can use the ‘File->Add to Library’ command.

Once you’ve done this, you can sync your device, eject it, and then you’re good to go.