Just follow the direction Robb wrote in that article. It works fine... If not, spend a little on the OnAirDesigns box... they work well too...
After dabbling, you might find that the mic preamp (especially the ArtTube) may be a little distorted (over modulated) at proper output and will eventually want to step up to a quality (but, reasonable priced) mixer board. Much better clarity and fine tuning. And expandable as well....
That SM58 is a nice mic, but, pretty pricey to dabble, as an alternative, can try a Behringer XM8500... it's less than $30 and sounds great for the price tag.