Using another Orbi Router as a Satellite that is hard wired

If you want four satellites (the two included in the three-pack, plus two additional ones), you should return the two-pack and just buy two satellites (from Best Buy, Amazon, direct from Netgear, whatever). Orbi routers don't have the ability to work as satellites. Short of that, your options are to just use the one additional satellite and put the second router on a shelf, as a spare, sell it, or, as someone else suggested, put the second router in AP mode and connect it with a wired connection to your main Orbi router. Or, use both Orbi routers as routers, and have two different Orbi networks that won't coordinate with each other (ideally, as peer networks, with both Orbi routers having their own direct connection to the modem, not hierarchically with one Orbi connected to the other one).