Click 'Wallet' in the main menu and then select the desired coin. That will take you to the balance page of that coin. In the bottom you will see several panes, including but not limited to: Deposit, Withdrawal, and Movements. Select the 'Withdrawal' pane and enter the destination address to see instructions on how to withdraw funds. For example, this is the BTC withdrawal pane:
Instead of an address you can also enter an email address of another SouthXchange user, in which case the withdrawal will be executed internally without hitting the blockchain. For BTC and LTC you can also enter a Lightning Network invoice (aka payment request) to send funds through the Lightning Network instantly and free of charge.