Step 1: Materials
Step 2: Hnefatafl
This game is an old viking board game. Its actually older than chess and the rules are really simple. I got the idea for this from this wonderful ible(http://instructables.com/id/Hnefatafl-Board-The-Viking-Board-Game/). He explains the rules and the construction of a beautiful wooden Hnefatafl board. Draw an 11×11 grid on one side of the cardboard. Draw an X on each corner square. I also added markers to remind me of the starting positions, but this is optional.
Hnefatafl uses 37 pieces. The defender has 12 warriors and a king while the attacker has 24 warriors. I kept the designs very simple and I left the attacking warriors blank, but you are welcome to add as much decoration as you like as long as there is a clear distinction between the attacking warriors, the defending warriors, and the king. A really interesting idea would be to carve individualized warriors onto the pennies hobo-nickel-style. Alternatively, it could be as simple as attacker=heads, defender=tails, and king=dime.
Attacker always goes first.
On each turn the player may move a piece any number of squares in any direction(up and down/left and right) until it hits the edge of the board or an occupied square. To capture a rival piece, you must surround/sandwich the target on two sides with your pieces. The king must be surrounded in all four directions to be captured. The objective for the attacker is to capture the king. The defender's goal is to get his king off the board or, alternatively, to one of the four corners(to make things a little more fair).