Generally you want to draw as much as possible, so that you can combo the opponent down.
With a combo deck, if you draw your whole deck, most likely you win.
The idea is that you OTK with either Grommash or Devilsaur, inner raged and sudden genesis'd, combined with your woecleaver. Sometimes you can do other combos too, like double Inner rage with double Grom, or grommashes coming out of your deck and your hand and you use your Garrosh hero power.
The time to dead mans hand is when you have woecleaver (before you equip it) and grommash at the same time in hand. Preferably you have drawn your genesis and inner rage too, but having 1 of the two could be enough, because the chances of drawing another one will go up after DMH. Why dmh the woecleaver? Because of weapon removals. Without Woe your deck sucks. Congratulations!