Oh, but that tutorial uses the Physique modifier. Just so you know, there's an alternative. Instead of using Physique, try using Skin. I've used both (Physique is an old standard, and waaaay back in the day when the studio I'm working at made ps2 games, our engine only supposed Physique, so I'm more than familiar with it) The thing is that Skin is probably a much better choice. -Especially- if you're rigging something a little more high poly. Super low poly is fine with Physique, but the more dense the mesh becomes, the more annoying it is to try and rig it with Physique. The envelopes in Skin help a lot, plus Skin has a mirror weights feature, but Physique doesn't.