First thing you need to make sure you have is a local copy of your Google Contacts from your CBBMail account. Follow these instructions to download a copy of your Google Contacts.
To import your contacts to RoundCube
- Log into RoundCube
- Click “Contacts”
- Click “Import”
- Click “Browse”, navigate to and select your save contacts file
- Click “Import”
After a few moments, the page will refresh and display your Contacts.