Steps to publish a new plugin and not change the default code

Hi all,

I need to finish a new widget plugin and publish that source code.

But, in my tests, I had to change the Nop.Web/Home/index.cshtml and Nop.Web/Shared/_ColumnsThree.cshtml

My questions:

There is a way to override this codes, and preserve the original source code?
If, there.. how can I proceed to acquire it?

Thanks