Anyone knows how to be able to download nzbs files on a mac?

i have an account to nzbs.org which has nzb files but cant cant get them to download i guess the content in my computer
I have download the program - sabnzbd
but i cant get the connection to work

i put the URL of the nzbs.org and its user details and notthing happens, its not able to connect or something
i dont know how this shit works
need help from someone that has some experience

Here's a good tutorial that explains everything, this stuff takes a good while to learn.

http://www.binaries4all.com/beginners/