Earlier versions of orbi RBS350 (satellite) and RBR350 (router) before ca. version 4.4.1.29xx would have to be set up in chained mode manually. If you have a house where one part of the house does not have coverage from the base the system will now automatically set it self up in chained mode. IN the outermost nodes you even have BOTH 2.4GHz and 5GHz service for the units that want to connect even if the back-haul is wireless and uses 2.4 or 5.
If you have experienced that some units on your Wifi network that were previously connected to your fiber or cable router cannot anymore be connected on your internal network – after you installed a set of ORBI mesh units – the reason may be that the ORBI system is not set up in access point mode. If it is set up in router mode, there is an internal firewall that acts in addition to the normal firewall you have in your cable or fiber modem. Log into the orbi unit with orbilogin.com and go to ADVANCED/Advanced/Router/APmode and select AP mode. Reboot the ORBI units and you are all set. All units on your Wifi network are visible (on your internal network). Read more here: https://kb.netgear.com/000061927/What-is-the-difference-between-router-mode-and-AP-mode