A solar access study requires that sunlight be added to the model. Sunlight is added the same way as all other lights, on the appearance manager. Once the sunlight is added a solar access study can be added using the motion study animation wizard.
There are two forms of Solar Access Studies, fixed date variable time, or fixed time variable date. These can be used to show a day or a season. All other appearances can be modified using the timeline like normal so it is possible to show the effects of the season along with the motion of the sun.
SolidWorks takes care of all of the details. Enter the obvious details and accept, then calculate the study. Play back to review.