You can upload a CSV, import your Google contacts (that contain email addresses), or manually add a new contact into the list
Step 1 – Click on “Contacts” located on the main menu bar at the top of the screen.
Step 2 – Click on “Import Existing” to import contacts from gmail, linkedin, or just about any csv source.
Step 3 – Select the csv type or choose “google account” to import from your linked gmail contacts.
Step 4 – Then click on get started.
Step 5 – Make sure all the CSV columns and information are lined up correctly, selecting the corresponding field from the drop down for each. Then click Next.
Step 6 – Preview the contacts, if all looks normal, scroll down and click Next.
Step 7 – Select tags to apply in bulk, or wait and add tags that get more granular later.
Tip – Segmenting contacts into separate CSV's before upload can speed up group tagging.