Custom Portlet Creation

Friend,
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

https://docs.plone.org/develop/plone/functionality/portlets.html#creating-a-portlet

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

https://docs.plone.org/4/en/old-reference-manuals/portlets/architecture.html

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

https://docs.plone.org/develop/addons/bobtemplates.plone/bobtemplates.plone/docs/templates/addon/portlet/index.html

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

thank you .