Proper WPS Sequence for Orbi RBK853 - Struggling

Thanks for sending the link. Appreciated.

Unfortunately it's a little light on details that can help eliminate if I'm getting things wrong at the router side or the appliance side. For example, is it just a quick press of the sync button? Or do you need hold it in for a time? Other Netgear devices ask you to press for 2 seconds etc.

Also it does not clarify if you can do this from the satellite device or if it must be the core router?

It's also unclear if you press the button on the router first or the device you are trying to link, then the router. 

I have done it before and should remember but just trying to eliminate silly messed up steps or if I have a more challenging issue

But thanks for the link all the same.