The current photon energy is displayed in the beamline control group of the SM_GUI main
window. Next to it you find a button which opens the dialog for changing the energy.
If you choose only to move the SGM, your sample (if any) will be out of focus afterwards. If you choose to adjust the sample, OSA and detector position, you should be in focus and ready to go for the new energy assuming that you have found and recorded your X-ray focus (Sec. 2.8).