how you can create custom modules in joomla?

Look at this:

http://developer.joomla.org/getting-started.html

http://docs.joomla.org/Tutorial:Creating_a_Hello_World_Module_for_Joomla_1.5

(And then time google a little first.)

Make your project to some Joomla module? You don't appear to know Joomlas naming. You're most likely considering transforming it right into a component, and not simply a module. A module is really a display-part. Components would be the bigger extension systems. However I can’t really tell without more information …

The Joomla docs for developers include several guides, explanations and lessons.

For Modules. Among them:

• Creating a Hello World Module for Joomla 1.5
• Creating a simple module

For Components.

While you appear to know PHP and frameworks, just peeking into existing modules and components might be just like effective (in the beginning).

This youtube video is a great tutorial on creating a Joomla 1.7 module on your own. It offers the files too:

http://www.youtube.com/watch?v=Qd93be8YRNY