WSRP Housing uses your server and faction to look up housing plots that the people at http://www.wildstar-roleplay.com/ have listed as open for RP. See the forum post there for more details.
Upon launching the addon, you will see a list of available places on the left. By clicking on the plat, useful information about the plot will be listed to the right. You can click a link on the right to visit the plot, or click on staff member names to see if they are online.