Airport express/extreme wireless connection to peripherals

This is going to be an incredibly nooby question, but here's my confusion. My Linksys router died. I've looked around and figure I'll try a refurb Airport Extreme. I've read all the bumph on what it can do. And here's the question I'm almost embarrassed to ask. I get that the airport has to be connected to my modem with an ethernet cable. But that anchors the airport and its usb ports to wherever I have a cable outlet for the modem (which will be the one behind my TV). So how do you use the other peripherals like speakers or printers or whatever? I've got a desktop PC that's connected to my printer and PC has a Dlink wireless router (the little jump drive thingie--you see my problem, little technical vocabulary--) that used to connect to my Linksys router before it died. So, from the bumph it sounds marvellous that I can run computers, speakers, printers and who knows what else off the airport--my vacuum for all I know--but how do each one of those items connect to the airport? Until RIP of Linksys, my macbook, PC and iPhone ran off the Linksys and a tablet is on its way which I hope will seamlessly connect to the airport extreme when it arrives.