how to include OpenNLP in eclipse project #17

As-salam-o-alaikum 
     My friend  i am using eclipse and NetBeans both and now moving to Natural language processing with Java and going to use OpenNLP for my project, but I have no idea how to include OpenNLP in my project and how to use its api's for my project.
Following are some steps which I have done:

1)went to Apache website and downloaded four(4) files which was linked their.
2)unzip. one of them and get four jar files so called maxent,tools etc and 
copied it.
3)create my project in eclipse and in the directory of my project I created a 
folder called "lib" and pasted jar files here and after that I did add build 
path.


now I couldn't create objects of these api's..... why???
am i missing some steps?
do I have to do something more ........
also I'm not able to use these statements

import opennlp.tools...
import opennlp.maxent...etc ... why