Custom Portlet Creation

I am trying to create a custom portlet. I want to create a custom navigation menu with only specified type of contents . Can anyone help me, I want to create a portlet via file system.

You are repeating - your basically information free question - again, over and over again:

What is missing from the documentation? What is the specific problem?

I need to know how to create it . Documentation tells how to override teh existing one but no how to create a new one.

There is clearly a link to

How to do the configuration ?
What to add in configure.zcml?
where to place the template?
what are the packages to be imported?

You don't need to write all the code from scratch. bobtemplates will
generate the boilerplate for you

That's exactly was the documentation recommends. But reading is sometimes obviously hard....

thank you .