which ethernet ports to use on xb7 router

Hello, I'm new to the forum. I have an XB7 router and would like to know how to configure it and which ports to use to support two ethernet CAT5 cables from two WIN10 computers, such that both computers are on the same "network". Currently the CAT5 cables are plugged into different ports and everything works however the computers are on different "networks". Instead of buying a 5 port switch, I figured there must be some way to configure the XB7 to "join" two ports.  Perhaps there is a different or better way?

Thanks, Bill