well its pretty easy logically, physically you just need to run the cables.
1st you need to make sure that wherever you move your modem/router, you can connect to whatever outside connection your ISP makes to it. As long as you can make that connection then you can move it wherever.
Then, you can physically run 1 normal Ethernet cables (RJ45 cat5e or cat6), from 1 port on your modem/router, into like a 4 port switch that you have in your room. Then you can connect your 3 devices into the switch, and they will have internets.