How to create a simple desktop environment?

Question

I want to know how to create a simple desktop environment, such as KDE, Gnome and LXDE, for Linux, or specifically, Ubuntu/Kubuntu, but I do not know how to begin and how complex it is.

I want to create a simple, efficient and lightweight desktop and to reproduce some good features from KDE, Gnome and Windows XP. I do not want to reinvent the wheel, I want to design the graphical interface and main dialogs.

I could use C++ with Qt, or maybe with X11 calls. A simple desktop like TWM would be the first step, then I could add taskbar, start menu, new features and play with new ideas.

Thanks.

Edit

I have installed icewm and I think it is what I need to begin. On the login screen, I can choose if I use KDE (desktop environment) or icewm (window manager). I do not understand what a window manager actually is.

I have downloaded icewm source code and I am confused. There are some concepts that I have to understand, such as, what happens after the login screen when the desktop is loaded, how a window works, etc.

Edit 2

I think I need a good tutorial. I have to understand how a Window Manager or Desktop Environment work. There are some concepts that I have to know.

Answer 1

This is no simple feat but by no means impossible.

Other people have done it, there are plenty of DE or WM out there so there is no reason that you, with patient, skill and lots coffee couldn't do something great.

Learn the difference between DE and WM.
http://www.ghacks.net/2008/12/09/get-to-know-linux-desktop-environment-vs-window-manager/

Test different DE and WM, maybe one does exactly what you want it to do?
http://www.engadget.com/2012/11/30/how-to-pick-a-desktop-environment-in-linux/ http://www.gilesorr.com/wm/table.html

Make your own custom DE
Here is a guide to get you started creating your own custom DE
http://maketecheasier.com/easily-create-a-custom-lightweight-desktop-environment/2010/08/10

After doing all this you should be better equipped to figure out what you actually want to do.

Fork a project and get started changing it!

Good luck