Underneath the Bids and Offers there is a text box where you can enter how much you wish to buy or sell. As long as the amount that you want to deal in is less than the sum of the bids (or the offers), you can enter the amount and click on “Calculate” to see the details of your potential trade.
This calculation will automatically match you with the best bids and offers in the market before asking you to confirm that you wish to proceed. If you do not like the terms, you can create your own bids and offers. You may also want to view one of our videos here for further information.