Here you have two options. First, use the Browse button to upload your .csv file but make sure that the first column of the .csv file must be emails or phone numbers (with country code). Second, directly paste your contact list from a .csv file in the Express Contacts field provided on the Create Contact List page.
First click on the Call Tracking menu portion then click on New Number to get started. According to your preference, you can purchase a transfer number to link with your phone number. A call will be placed on the transfer number when your customer taps on the CTA "Call" button.