Hi. How far have you got with the extender?
Do you have internet access with ethernet and wifi devices with the AC1600?
On AC1600, wifi and wps must be enabled.
The extender has to be placed within range of the AC1600. You can tell by the 2.4G and 5G signal strength leds on the extender.
The extender has an ethernet port to test the wifi connection back to the AC1600.