it took me a minute to figure it out too, so no worries
i use the countdown only trigger method and adjust it to 10 sec but thats by preference
-when you hit the start button it will start counting down
-simply get the screen to how you want to take the pick, even if you hit the back button to get to the home screen, or the phone dailpad screen for example, drocap is still counting down to zero and will take the pic when it does
if you have SDcard notification on, your phone will tell ya by that notification that it took the pic