creating themes for Nokia N97 mini

Hello everyone
This is my first post in the J2ME,
actually I bought a new Nokia N97 mini few days ago and want to build sample applications for that

I learned how to create the applications for phone from nokia forums
but when I created Hello World application in netbeans ,
auto generated code was completely new to me
I just want to learn that

please provide me link for a nice tutorial that will make me understand J2ME default methods

This looked like default methods in applets
please help
I am eager to develop something for phones

and more importantly I want to create simple themes for mobile
how can I do that?