When I make appointments I am seeing different colors of shading. When I open a paticular appointment I see Appoinment Details and then Send Using: directly underneath that. The one I am looking at now has a purple box and it says Facebook. It looks like I have three options, Device Default, and Facebook. I think I would just prefer one color shading. How do I set it that way, and how do I go back an make all of the calendar appointments that way?

Go to calendar, options, then you will see each calendar, then click on that calendar, set the color, do the same for every other calendar.

I'm not clear, why do I need more than one calendar? How do i cancel/delete the other calendars?

you will always have device default
you will always have one that has your email address

and if you have the facebook calendar option checked, you will always have that.

How do I change everything to device default?

you have to duplicate ie.e reenter all appointments under device default
and then delete those out of the other 2 calendars

You have to delete the facebook calendar service book in order delete it. Also, your email address will have its own calendar, you can delete, but if you resend the service books, it will add the calendar.