Yes you can.
Head to the Invest Section on your Moneybase and type the name of the instrument you would like to trade in the search bar. Click on BUY and complete the details of your order including buy/sell, number of shares, order type and validity.
Ensure that the Order Preview toggle is enabled. You can now click on Place Buy Order and your Order Preview will be shown.
Please check this screen thoroughly to ensure that the order details inputted match your intended instructions and then proceed accordingly.