If you entered the correct FL of the guide scope and pixel dimension then the lines in PHD graph represent 1 pixel deviation from the centre line...4 lines 4 pixels.
If you run a correct PHD calibration then the star is generally locked on the centre graph line (and centroid of the guide star) and the Ra and DEC oscillate somewhat above and below the centre line.
However it probably doesn't matter if the the graph RA or Dec is above or below as long as the Ra and DEC are not oscillating wildly around with large deviations.
If the Ra and DEC are not on the centre graph line then something is up with the PHD settings or calibration.
As long as you are happy with you image (they do not trail stars) and since you are beginning with PHD guiding I suggest that you ignore the PHD graph and just deal with the basic PHD interface at this stage.
If you Osc is .03 then that appears a bit low (but not necessarily) ..something is probably not right but do not worry unnecessarily unless you are unhappy with your guiding and images.
Looking at the graph and putting all you attention into it will have a newbie running in circles for something that may not be an issue. Again if you guiding is ok spend you time with the basic interface
and with experience (or if you are having issues) then move on to the graph.
What I would do is try another calibration star and see how it goes.