Create a extra outside of modx installation

I am trying to create my first extra (Transport Package).

I have did research on this
http://rtfm.modx.com/revolution/2.x/case-studies-and-tutorials/developing-an-extra-in-modx-revolution

But getting following errors :
Warning: include_once(C:\xampp/modx/core/model/modx/modx.class.php): failed to open stream: No such file or directory in C:\xampp\htdocs\doodles\_build\build.schema.php on line 3

Warning: include_once(): Failed opening 'C:\xampp/modx/core/model/modx/modx.class.php' for inclusion (include_path='.;C:\xampp\php\PEAR') in C:\xampp\htdocs\doodles\_build\build.schema.php on line 3

Fatal error: Class 'modX' not found in C:\xampp\htdocs\doodles\_build\build.schema.php on line 4

My system Information

Have xampp installed in my windows system.
There are two directories in htdocs folder 1) modx (Modx setup) and 2)doodles (Modx is not setup)
In doodles directories there are another three directories
-build
-assests
-core

What to do to go ahead to complete my component?
Is there any other way to create component manually?

If you follow the directions exactly, that tutorial will work. It's just difficult sometimes to understand exactly what it's telling you to do. It usually takes me four tries to get the whole thing working.

There is also MyComponent http://bobsguides.com/mycomponent-tutorial.html

MyComponent is really useful if you plan to update your component and/or create more of them.

This might help with your current problem: http://bobsguides.com/blog.html/2013/07/13/using-modx-outside-of-modx/

Thank you BobRay

I am also using Mycomponent to create new extra. Its a good one to create a transport package.

Thing i want to know is :
I have created a CMP page using migxdb. I want to create a transport package in which i can use this CMP page when package is installed in any modx system.

You can find my discussion here :
https://forums.modx.com/thread/91911/has-anyone-had-the-chance-to-build-a-component-which-works-similar-to-form-save-in-modx?page=2#dis-post-502568

Clear thing is Combine CMP Page (Created using Migxdb) with my package (created with Mycomponent).
What should i do ?

I'm afraid I haven't yet created a package that uses MIGX or Migxdb. In theory, it should work, but it will depend some on where Migxdb puts any files it uses. I'm also not sure if MyComponent could handle MIGX TVs.