New tab in customer with manual

[newb]

I want to add a new tab in customer's page that will explain the way the app is working. I just want to add a small text. I added a new tab next to the "new ticket", "my tickets" etc. and i have created the pm file for the new module, but i don't know how to continue! Can anyone help me with it?

[jojo]

have a look on the devel book on http://doc.otrs.org

[newb]

I have searched the documantation, but I couldn't understand what to do!