If you have another wireless router, you don't even need the standalone switch. All you need to do is give the second router a unique static IP in the same network as the primary router (so letâ€™s say the primary is 192.168.1.1, maybe make the second router 192.168.1.2), disable its DHCP server, and connect them LAN to LAN (do NOT use the second routerâ€™s WAN port!).
Netgear has a pretty good illustration of this setup. It references their own gear, but the principles apply to ALL routers.
The primary router in their example happens to be wire-only, but that only means you need to use different channels to avoid interference.
NOTE: You can, if you want to, put the switch between the routers, doesnâ€™t affect the setup one iota. At 50 ft., not using a switch shouldnâ€™t be a problem in terms of Ethernetâ€™s reach (100m max before needing a repeater). But if you feel it helps, itâ€™s certainly not going to hurt. It would probably be more useful behind one of those two routers to expand the # of available ports.