When you make a sale, your earnings for that sale will remain in the "Pending Sales" box for 7 days. After 7 days, the earnings move to the "Earnings to be Paid" box. You can see this on your Payouts & Earnings page.
Once you reach your payment threshold, Earnings To Be Paid will be sent to you on the 1st of the month or the following Monday, depending on the option you choose in your Payout Settings. Custom payment thresholds will be paid on the following Monday after the threshold has been met.