To manually control the Piezos, position the cursor over the according piezo position indicator in the lower left of the main window, press Ctrl and use the mouse wheel to control the piezo.
If this does not work, check the alignment settings via menu bar => Paremeter => Alignment. Select the Handbox tab and check that the Handbox Tilt Fine [V] value is non-zero.
Hint: Switch off the stabilization routine during manual control by clicking on the three round buttons next to the numeric indicators on the left of the main window. A green button indicates the according stabilization being active, a red button shows that the stabilization is switched off.