The following guide only applies to the Windows version, but setup on OSX is very similar. Note that you need a valid Usenet account to use this software. Easynews is what I use, but there are many others to choose from.
Installation Guide
To begin, download the appropriate version for your operating system here. Step 1. Download and run the installer, clicking next until you see the section where you can select the tickbox for “NZB file association”. Select it and click next to finish installing.
Step 2. Once it has installed, a web browser will open with a list of languages for you to select from. Select your language and click “Start Wizard”. Step 3. The first thing you need to enter are server details, which will be provided by your Usenet provider. I have filled them out with the Easynews server details below. Click “Test server” once you’ve filled these out. After a few seconds it should say “Connection successful!”. If it doesn’t, then you may need to recheck your server settings. Click Next.
Step 4. You can select whether or not you wish to be able to access SABnzbd from another PC on your network. The choice is up to you. You can also password protect it. Click Next.
Step 5. This next section allows you to enter your account details from various newsgroup indexing sites. This is for automation and best fiddled with once you get your head around the basics of SABnzbd. Click Next.
Step 6. SABnzbd will tell you that it is restarting and a few seconds later you should be presented with the following page, which is the download management area.
Step 7. Just a couple more things you probably want to set before you set SABnzbd loose. Click Config in the top left hand corner, then click Folders in the menu on the left. Changing the Temporary download folder and Completed download folder to locations of your preference. If you want you can also specify a “Watched” folder, where NZB files that are downloaded will automatically be queued up by SABnzbd for processing.
Step 8. Test it out! You need to feed it a NZB file to test out the download functionality. I’ll leave this part up to you – there are a wealth of resources from which to grab NZB files (e.g. nzbmatrix, newzbin2.es, binsearch.info etc). Some are paid and some are free. For the purposes of this guide I used binsearch.info and searched for “trailer”. I found a Mass Effect 2 trailer in the search results, ticked the checkbox next to it and clicked “Create NZB”. This generated a NZB file that Google Chrome automatically downloaded to my Downloads folder. As I had set my downloads folder to be the watched folder in SABnzbd, it found the file and started grabbing it from Usenet. As you can see in the screenshot below, the trailer downloaded at a healthy ~3mb/sec.
Once the file finished downloading SABnzbd automatically extracted it. I could then find it in my completed folder and play it with VLC, as per the screenshot below.
Conclusion
There is obviously much more to SABnzbd, and not all of it can be covered in this article. Briefly, some additional things that may be useful are noted in the image below. If you have any questions, please ask!