Just bought a home with a nice in ground pool. I have an Intermatic PF1202t dual circuit timer and I'd like to install additional trippers for a second pump run. It uses the silver and gold trippers with the small screw. How do I install these on the dial? Just reach up and insert them behind the dial or do I have to remove something first? Also, do I have to turn off the power first? Sorry if this is a really basic question, but I'm a new pool owner.