[Trisquel-users] Help with modify a package

[julian]

Hi.

I would like to modify tasksel package in Trisquel 8, because I need to add  
web server as in Trisquel 7.

I'm reading https://trisquel.info/en/wiki/package-helpers . I created a  
folder named "src", and then I get the source with "apt-get source tasksel".  
This one downloads the source, but I don't understand how that it works, and  
I don't know that package-helperers how works.

Can anyone help me with an example or explain me how can I modify a package  
for helping Trisquel project?
Thanks!