Would someone give me the correct method of conducting an ILS or non precision approach using the GTN 750 intergration? Do I switch the CDI or OBS selector on the bottom of the 750 display and if so, to what and at what point when using the GPS in NAV mode on the autopilot? What about the PFD? Any help with the correct steps in setting up this phase would be appreciated. Thanks.

If you switch the CDI on the PFD, the GTN should follow.

 

Lower left on the PFD, by the "Preset" text