So first, you'll need to do that from the EMS side of the setup. Next, grab a copy of the D180 installation manual from http://docs.dynonavionics.com. You need to have 3 things right before you'll have a working flaps indicator: You need to set the appropriate GP input to flaps; you need to have one of your info items set to flaps; and you need to calibrate. Most of the instructions you're after are on page 6-7, and the couple other things you need to do are referenced from that page.