Quicksilver Plugin to send an IM to an Adium contact

Send IM to Contact.scpt

# Adds "Send IM to Contact" action to any text in Quicksilver.
# Requires: Adium >= 1.4.0.
# Type a friend's display name or IM handle, press Tab to bring up action list,
#   and select or type to autocomplet "Send IM to Contact."

using terms from application "Quicksilver"
	on process text im_name
		tell application "Adium"
			set theContact to the (first contact whose (display name contains im_name) or (name is equal to im_name))
			try
				set theChatWindow to the first chat window
				tell the account of theContact to make new chat with contacts {theContact} at end of chats of theChatWindow
			on error theError
				tell the account of theContact to make new chat with contacts {theContact} with new chat window
			end try
			activate
		end tell
		
		tell application "System Events"
			tell process "Adium"
				tell the first menu bar
					tell menu bar item "Window"
						tell the first menu
							click the last menu item
						end tell
					end tell
				end tell
			end tell
		end tell
		
		return nothing
	end process text
end using terms from

Can you explain how to use the script?