Steps to develop a shipping plugin

[bpinhosilva]

I saw the official documentation, but there are doubts in my mind. I'd like to develop an open source shipping plugin to calculate the shipping prices, but I don't know to start. Could somebody give some tips to start my development?

I saw some class to extend, but, I'd like to obtain comprehension to start my job.

This plugin will be specifically because is about an different shipping enterprise in my country.

Thank you!