All right, so it’s not so much a house rule as it is one that should have been explained in the published book. Not sure how I missed that, but here goes (it’s really simple):
Initiative describes the order in which players and enemies act in a battle or other type of contest. Anytime the GM calls for a battle or a test of skills where order is important have the players each roll 1D6 and add their Cunning skill to the result of the roll. Ties are solved by the player with the highest Cunning going first. If two or more people have the same Cunning skill, compare Agility. If those are still tied, just have them roll off to see who goes first (highest number goes first).
Remember (as a GM) to roll for the enemies as well. Note all the numbers and the initiative order goes from highest to lowest. When everyone has taken his or her turn, start back again from the top of the initiative order under the battle or challenge is concluded.
It’s as simple as that. Sorry for the omission.