Go to CRM → Contacts and click Import (or the ⋮ menu top right). Upload a CSV with columns such as `firstname, lastname, email, phone, company, tag`.
Senly shows a preview and lets you choose per column where the data goes (column mapping). Existing contacts (matched by email address) are overwritten; new contacts are added.
Max 5,000 rows per import. For more: split into batches. The import is GHL-compatible — a direct export from GoHighLevel can be imported 1-to-1.