1. Click on "Contacts" on the toolbar at the top of your screen.
2. Search the contact you would like to tag.
3. Click on the + sign next to "Tags".
4. If you have previously used a tag, it will appear in the dropdown.
5. If this is a new tag, start typing the name of the tag in the "Create or find a tag" box.
6. You will then need to pick a color for the tag.
7. Click "Create a New Tag".
8. The tag will automatically appear on the contact.