Hi boeing247.

Have you read KB #6061? This is an in-depth explanation on flying the 707 using the DNS (by LOU). It's too big for me to add in here for you, although I do believe that it was in in a Topic in this forum as well.

To use heading select, switch the Mode Selector Knob on the AP to HDG. You can't have is set to NAV and HDG, it is one or the other. ;)

Mark