I got in nginx instructions to the step 5. but don't understand how to start or stop or how this works or why I should stop it once I start it.

I copied your script to the end of the .conf file (I'm a 44 years old script kiddie and know how to copy scripts without understanding them) and saved. After that I opened the link to the init.d instructions and my mind almost exploded while I tried to figure out what everything means and works. Could not understand anything, really, not kidding.

And by the way I first tried dpkg -i nginx in the location but there were missing dependencies so I enabled extras-devel repository, updated and tried apt-get -f install and got it installed.

But I haven't now load any module cause no module was found. Do I need to do that and in what point? Almost there to be able to try.