Really simple. Got it on my 1st try/game. If you're not familiar with Hockey, you get called for icing when you pass/shoot/dump the puck and you are behind the red line (the red line dividing the rink in half). The only time this is permissible is when you're on the PK (Penalty Kill); if this is the case the Icing rule does not apply to you. So when you're not on the PK be sure to be pass the red line before letting that puck leave your stick.
Good Luck!!