- Install the "Sync" app in Cozy. It allows to sync your contacts and calendars through CalDAV and CardDAV.
- Then, open the Sync app and go to "Server credentials". You'll find your user name ("me") and a random password there. Use these credentials (not your Cozy username/password) for CalDAV/CardDAV.
User name: me
Password: see Cozy Sync app
Contact group method: groups are per-contacts categories (mapped as labels in Cozy)