providing a "landmarks" section in the nav document

Hello.

I created EPUB file using Indesign CC.

After uploading, I got the following error message.

Error / NAV: Fixed layout Epub books must identify the start of the book’s main content by providing a "landmarks" section in the nav document with at least the "epub:type=bodymatter" attribute included.

If I modify my file by using Indesign, how I should do?

I appreciate your support.

Thank you,

Masashi Harada