Before you make your withdrawal, please take a moment to read this article which runs through all the considerations of doing so.
If you still want to withdraw money, sign into your dashboard, click Funding from the top menu
Click the icon for the bank account. This will move to the "To" box
Click "Withdraw Funds" and enter the amount you want to withdrawal
Click "Review Withdrawal"
Confirm the withdrawal information and click "Confirm Withdrawal"
Your withdrawal should process in 5-7 business days