If its this style as mine, if you press the top button it should cycle between clock, odo, and MPH. get it to show the clock then let off the button and press and hold the bottom button. It will start advancing slowly at first but then in bigger increments. when its close to the time, let up and then re-press the button to go back to slow advance until you have the time. The clock does not have an AM/PM.
Once set, then let off the buttons and a few seconds later the pod will display normal.
2007 Arctic Cat 400 4X4 LE
2010 Arctic Cat 366 4X4 SE
2012 Arctic Cat 450 4X4 H1