The install.txt file says you should now type the command:

cocoon servlet

When you do this, another command shell window should appear. About 14 lines are output ending in the line:

08:34:52.315 EVENT  Starting Jetty/4.2.23

It then does a lot of work. After about 4 minutes it outputs some more lines ending in the lines:

08:38:39.412 EVENT  Started SocketListener on 0.0.0.0:8888
08:38:39.412 EVENT  Started org.mortbay.jetty.Server@f0eed6