For given envirenmental values (temperature and pressure) you do an EPR experiment for different orientations of the external magnetic field: from  to -crystalline directions. This will give curves for the g-values (the principle components). In Fig.3 of the paper discussed in the video they indicate set of axes with ‘cb’. So different indications in the spectrum correspond to other sets of axes. I then wonder if changing the envirenmental values will result in these different sets of axes. If this is true, then the previous procedure is repeated for a different set of envirenmental values.
From reading the pdf file of the next task, I would like to add that the different principle components are determined by measuring in the corresponding principle axes of the crystal individually and changing the orientation of the magnetic field and for each magnetic field orientation you measure the current principle g-factor. Then you change the direction of the crystal to measure in the principle axis of another principle g-value and repeat by changing the orientation of the magnetic field and measuring each time again.