Apple's iBooks Author is an excellent tool for creating multimedia ebooks, but there are some elements of using it that can be confusing and or frustrating. While you can figure it all out on your own as you go, that's how I've been going about it, you can save yourself a bunch of time by reading a good guide ahead of time. I wish I had done that.
Publishing with iBooks Author is a free 110 page publication from O'Reilly Media. I just discovered the guide a couple of days ago and I wish I had found it earlier because it would have saved me a lot of time in learning how to use iBooks Author. Publishing with iBooks Author covers everything from copyright, DRM, and the End User Agreement to templates, layouts, media insertion, publishing, and distribution. You will have to register for an O'Reilly Media account to download the book (that does take a few minutes and requires email verification) but I think that's a small price to pay for an excellent free ebook. Publishing with iBooks Author is available to download as an ePub file and as a PDF.