There are two main ways to get subscribers for your Digest:
1) Make your Digest public and share it with others
Click the share button on your Digest and set it to public to grab the shareable link. On the Digest page, people can subscribe to receive your Digest by inputting their email address at the top (note: subscribers will receive a double opt-in email to confirm their subscription to your Digest.)
2) Manually add subscribers
Click the subscribers icon in the lower left corner of your Digest.
From the subscribers screen you can manually add individual subscribers, or import a list of existing subscribers that you are porting over from another service (note: subscribers will not receive a double opt-in email when you are manually subscribing them.)