1. Go to app.narendi.com. You are sent to the Wiply login page: sign in with your Wiply account.
2. The first time, the app asks you to verify this session with your security key: copy it from wiply.net (see how) and paste it.
3. Your chats, groups and contacts are the same as on wiply.net.

From a chat window on wiply.net you can jump straight to the same conversation in the app: ⋯ → Open in Narendi.