[GoLightly]

That's the explanation? I'm more confuzzeled than before you answered.

Multiple drill, would be more than one drill in a day. Am I close?

IDT, inactive duty training. How am I doing?

AD, Active Duty. Right?

ADT, Active Duty Training. Tell me I'm not a total doofus if I have all of this wrong.

[OneLoyalAmerican]

Seems you are seriously trying to learn. My highly biased personal resource: http://www.uscg.mil/hq/reserve/drill/windex.htm