Need help with add a customised button to top toolbar.

Hello All,

I am working on a project to add a customised button to top toolbar of
Writer.
I've built the source and had some other modification done.

However, i found myself lost in the large code of framework/sfx2, and don't
know where to start.

Is there any good example i can get clear idea of the whole thing from the
current source code or and external material that can help? Can someone
figure it out?

Thanks!

-- 
yours sincerely,
                     Jeff