Open your Dashboard and locate Wallet Credits block. Make sure you have some available credits for payout. Credits are available for you after you request them from students and they confirm that (manually or automatically after 7 days). You can request payout at any time - a few times a month or once in a few months - it's up to you.
Click on View Credits link
Then click on Request payout
Confirm payout request and it will be to administrator for approval. After this you funds will be transferred to your connected bank account.