Adding contacts manually can take up a lot of time, especially if you have a large list of cast and crew that you work with. While there isn't any way for you to drag-and-drop your contacts (via .csv, .excel, Mac contacts, etc.), there's an alternative way to get contacts uploaded.
Step 1 — Click on Import Contacts
On the Contacts page, click on the Import Contacts.

Step 2 — Paste your email addresses
In the pop-up, you can enter multiple email addresses at once or simply paste a list of emails.

Step 3 — Click Add Contacts
After you have added your email addresses, click Add Contacts.

How do I export and download my Contacts in a .xml / .csv format?
Currently, there isn't a way to download your contact list like this.