Is it always active? If not, when should I use it? How do I activate it? thanks for schooling a newbie like me.

 

DTC (Dynamic Traction Control) is NOT active when you normally start the car. DSC (Dynamic Stability Control) is active however.
DTC is more like a feature...it lets the wheels spin out a bit, but will not allow the car to slide sideways (or will prevent this as best it can...physics still apply )

DTC can be used when getting out of snow where a little wheel spin is needed, or having a little fun with less risk of raising your premium. DTC is activated by pressing the DTC button once. DSC is de-activated by keeping the button pressed for about 4 seconds.

DSC will always stay on even when DTC is on until you de-activate it fully by holding the button for about 4 seconds.



*Schooled.

 

Perfect explanation

 

Great textbook explanation.
In layman's terms; DTC is wheel spin while DSC is stability and lateral movement.