Idiot's Guide to Connecting HR21-100 to LAN

I've read the network threads here. They are informative, also confusing.

So I ask: What is the simplest and least expensive for connecting the HR21-100 (or equiv) to an existing home network.

My network is a Linksys WCG200 combo cable modem and wired/wireless router hooked to iMac running OSX & VMWare Fusion/Windows XP. Works fine for all computers in house.

I tried Netgear's dual wall-plugged connectors and could not get them to work. I would prefer wireless connection anyway.

If someone could do an "Idiot's Guide" (in addition to the exhaustive treatment already here) that would be very helpful to me and, I suspect, many others.