Need How to On EX6120 settings so Device light stays green

[Momaui]

Aloha,

I have Mac computers running ystem 10.15.7 using an Airport Extreme Router V 7.9.1. I try to use this EX 6120 to extend the signal in my downstairs. Netgear support says the internal setting need to be adjusted on this device as the green light that shows device connection does not stay green. It cycles from green to yelow from time to time. All the other lights are green. Can anyone give me the "how to" properly update/change the settings for this device so it will talk to my computers? Many Mahalo's for your help and Aloha-

John