When a customer pays an online order, your earning first shows in Held (Pending) on the Payouts page, with the words Awaiting settlement under it. It is yours, but you cannot ask for it yet.
When it becomes available, it moves to Available Balance by itself. You see a Hold Release row on the Transactions tab, and a Funds Released note in your bell with the amount and the number of orders.
To see exactly what you can ask for today, press Request Withdrawal: the dialog shows the amount under Free to withdraw.