Bend the flaps with pliers. Jagged tin edges can cut. Wear gloves for safety . Push the stick through the holes so an inch sticks out one side and the other end is 1 or 2 feet long. Wrap the stick with string so the can won't slide along it.
Most spike fiddles have three or fewer strings.
Tie one end of the strings to the short end of the stick, then stretch them over the soundboard end of the can. Pull the strings tight and tie them either through a notch in the end of the stick, to a peg, or to an eye screw. Spike fiddles often have a moveable nut. When you slide the nut up or down the neck, the pitch changes. To play a fiddle you need a bow.