How to traverse and click on Next & Cancel Button (On PopUp) using selenium webdriver

I have a pop up window on webpage where in i need to click on "Next" and "Cancel" button. I have tried navigating and find the css selector but couldnt able to locate and click on Next & Cancel button. Below is the Fire bug things when i got after hovering on Next & Cancel Button.

Please help how to click on Next & Cancel button

<div class="ui-dialog-buttonpane ui-widget-content ui-helper-clearfix">
    <div class="ui-dialog-buttonset">
        <button class="ui-button ui-widget ui-state-default ui-coer-all
         ui-button-text-only" type="button" role="button" aria- 
         disabled="false">
             <span class="ui-button-text">Next</span>
        </button>
        <button class="ui-button ui-widget ui-state-default ui-coer-all ui-button-text-only" type="button" role="button" aria-disabled="false">
            <span class="ui-button-text">Cancel</span>
        </button>
     </div>
</div>