indenting first line of paragraphs

If you're using Word, you can set the tab spacing so it happens automatically when you start a new paragraph. On the menu bar, choose Format>Tab, then change the default setting to 0.2.

Also, you might want to use the formatting options available in Word to create an ePub Style that includes this specific setting. It might take a while to figure things out, but it's worth it, not to have to (re)invent the wheel for each new project. Good luck!

You can check their site for specs, but I think you're better off setting your indents in the "paragraph" section of your document. I design magazines for a living, and anytime I get copy in with tabs for indents I have to go in and take them out manually and that's really a pain. I can only imagine how bad it would be for a whole novel. I assume the publishers have a layout program they're using to format the book, and setting some kind of style that automatically indents paragraphs to their specs is likely. It's easier to do that if you have yours set to paragraphs and not tabs.