How work Java object ?

Hello !

I work on a Digi connect me, and i have to make an applet java with Jbuilder. I download the Common.jar and Configapp.jar an place inside Jbuilder but i have some problems :

I don’t know how they work ?
I don’t know if Jbuilder has a good configuration, because they are not graphic ?
I don’t know if i make an applet, i need to create with the Common.jar and Configapp.jar inside my applet ?

thanks for answers

joel