Depending on your preference, the following methods and their corresponding tools will suffice:
Method 1: In-browser editor
Here's a quick tutorial to help you get started.
Method 2: Bookiza Abelone
Bookiza is a book reification framework, or put simply a "book baking" tool. It's a FREE and open source framework written and maintained by the Bubblin team and contributors.
In comparison to the in-browser editor (method - 1), Bookiza is a lot more low-level tool that requires setup and involvement. It handles your manuscript smartly - as if it were an app - and lets you collaborate with friends using the elaborate developer toolchain.
Visit site http://bookiza.io for more details.
"Bring your book to life with full-bleed imagery, visuals explanations, @font-faces, WebGL or AR/VR, resources over CDN, audio, video, animations and a whole lot of interactivity, but do not lose sight of your story." - Marvin Danig, Founder