You must log in to your account, then you must go to Wallet / Withdrawals and click on the currency you wish to withdraw and then enter the address where you want to send the coins and enter the amount and click sent (Example - DASH):
If 2FA is enable on your account, you will be required to enter the Google Authenticator Code before you can Submit the withdrawal request.
After submitted your withdrawal, you will receive a confirmation link by email to process your withdrawal.