Open the affiliate from Affiliates to see their "Referral link" and "Their portal" address.
A click on their link counts toward their commission for a set number of days, shown as A referral link counts for (days) under Program settings. Their code also works if a buyer types it in at checkout, with the same discount.
The affiliate signs in to their own portal with the email on file: they enter it and Purity emails them a sign-in link, no password needed. In the portal they see their link, clicks in the last 30 days, pending and approved commission totals, past payouts, and any approved posts.
Commissions are only earned when an order is actually paid, however it was paid. A refund reverses the commission.