To transfer EOS to your DSX account balance you will need to use the wallet address and a Memo which is associated with your account. You can find that information in Account -> Balances section.
Click Add EOS. You will be additionally notified that a failure to provide Memo with your transfer will result in the loss of funds. Accepting these terms will allow you to see the address you should use to transfer EOS to DSX.
Due to the specifics in EOS addressing, Memo - is the ultimate identifier of the sender. If you fail to enter the Memo correctly, we won't be able to allocate your transfer and add it to your balance.