In summit demo, I saw a new field "previous page" was available. But I can not find it in my workspace. I am wondering how to enable this field?
You can use the getPreviousValue plugin to do this
Hope you are talking about the 'Next Page' and 'Previous Page' report in Adobe Interface.
Sorry, it is not available.
Rather you have Path Flow!
you can create a segment to get your prev. pages.
Previous page was a custom dimension. The logic used was to set a cookie on each page with the page value, then reference the cookie on the following page and put it into an eVar.