Notes disappeared from new iPhone 6s?

I recently upgraded from an iPhone 5s to a 6s. I didn't check at the time but now I realize that all my notes are gone. How can I get them back? If I search on the phone, the search results list the note that I'm looking for but when I try to open it in notes, there is nothing there.

All the online help docs tell me to go to icloud.com but there isn't anything there. How can I recover the notes that are gone?

Thanks.