To add a contact to a group:
- Open the Remember The Milk web app.
- Click on 'Contacts' at the top of the page.
- Click on the 'Contacts' tab (if you're not already there).
- Select the contact(s) in the contacts list who you wish to add to a group.
- Click on 'More Actions...'.
- Select a group under 'Add to...' in the dropdown.
The selected contact(s) will be added to the chosen group.