When importing a CSV, you'll want to make sure it's formatted properly to successfully upload your List.
The first column should be titled: first_name
The second column should be title: last_name
The third column should be titled: email
Optional column: phone_number
Workshop also supports uploading custom attributes to be used for targeting communications or personalizing emails. Include columns with information like department, title, salary, etc. Read more about how to utilize CSV uploads.
If you would like to download a template for the CSV importer, you can find one here:
Sample Workshop CSV file