@Tony_Stark Welcome to the Rockstor community. Oh and I agree completely with the Docker approach suggested by @Dragon2611. Definately the way to go especially given the future plans for Rockstor’s Rock-ons which are simply Docker units that happen to be tied into the UI. This way if you get your Sabnzbd Docker definition as you like it there is a high chance that others will like it also and if you were happy with a GNU AGPL v3 licence then you could submit it to the rockon-registry repository. for future inclusion when the outlined framework in the wiki post linked above comes into being.
Of course in the meantime you can be using and refining your Sabnzbd docker config and running via the command line.
Hope that helps and do let the Forum know how it goes; or ask any further questions of course. I’m afraid I’m a bit of a newbie docker wise but there are definitely other here who are willing and able to assist.