Sorry dude, no idea why my link's not working for you. Don't search it, just click on it, it's just a link to another thread on this forum. You can search us out on Facebook too.
We meet at Burleigh Brewing in West Burleigh, 6 PM, second Friday of every month. There are a couple of homebrew stores on the Coast, but truth be told, grains, hops, yeast and everything else you need is best bought from Craftbrewer in Capalaba (sponsor of this forum too). A "local homebrew shop" (LHBS) proprietor that knows his/her shit and actually gives a stuff is a rare thing. Sadly they are few and far between. Follow the advice of the lesser ones and you'll probably get the same disappointing results you've experienced so far.
This is not to say that you can't make a great beer from a can of goop and few extra bits, but it requires a bit of extra effort and expense. When you weigh this against some of the budget/time-conscious all-grain (AG) methods that have been pioneered and refined in recent years (many by members of this forum), you'll probably just want to jump straight into AG. I wish I had.
In answer to your question about when to add yeast with Nick JD's method: you add the yeast at exactly the same time as for any other kind of beer: when the wort (this is what we call the sweet liquid before yeast is added) is at the right temperature (around 18 C for ales and 10 C for lagers is a good general rule). You can leave your boiled wort to cool in the kettle, sealed as best you can against outside contaminants, and ferment it in that vessel, but of course you can't use that kettle to brew again until the beer is finished fermenting. Ideally you'll leave it in "primary" fermentation for a week or more. At the same time that you add yeast, your wort also needs to be aerated to provide the yeast with the oxygen it needs to do its job. Transferring it from the kettle to the fermenter with a bit of splashing around helps to achieve this.