View or search your contacts
Click the contact list name or click Search in the Actions button
This will open the contact list preview and search page
Click the Add Rule button to search your contacts attributes, for a more in depth explanation on Search Rules see segmenting
Click the + sign to add additional search criteria
Tag contacts by entering the tag name, selecting the contacts, and clicking "Add Tags"
Remove tags from contacts by selecting "Remove Tags" from the multi-function button drop down