If the Next/Last Activity card view is empty, simply click on the '+' icon located in the top right hand corner of the window.
This will produce a drop down window titled 'Choose Widgets'.

From here you can select/deselect the Last Activity and Next Activity views.

You can also change the order in which they are displayed by holding the mouse cursor over the Last Activity/Next Activity title bars and dragging the box into a order of your preference.