Take a look at the two stickied threads where Huss48 has uploaded quite a bit of material:
Re: IT Applications Resources For Outcome 1, there's also these resources:
Unit 3 Outcome 1 ResourcesAssuming this is the Nelson book you're talking about, Chapter 2 is the Online Communities topic, right? In general, for that SAC you'll be given a problem where an organisation wants an 'online community' created in order to enhance their organisation and what not. You'll be expected to follow the problem solving methodology and create a "prototype" website (basically means you don't have to worry about details such as server-side scripting, databases etc. - it just needs to decently represent what a functioning version of the website would look like).
If you take a look at the end of the chapter, there will be a couple of pages on 'preparing for the sac', and that will outline in a bit more detail of what I've said above (the practice sacs in that above thread I linked to should also give you a better idea of what you'll be expected to do).
Feel free to ask for help here.