Nzbget is a downloader. Drunkenslug is a usenet indexer. You can’t configure an indexer in a downloader. You’re probably thinking about a usenet provider. Usenet providers need to be added in the configuration of your downloader.
A decent indexer costs money and a provider costs money.
To automate everything, you would want to take a look at Sonarr and Radarr.
Btw. I would recommend Sabnzbd over Nzbget anyway.