Depends on the exact rules to his, but typically speaking there are multiple locations (5) where you ride (I assume motorcycle, but around here they do them on quads, and snowmobile too) to. At each location you cut a deck or pick a card. This is usually recorded on a score card, after you complete the trip you have a full hand recorded on your score card. You then return to the club house and receive prizes based on how good your poker hand was.
Usually done for charity. Highest hand gets either the grand prize or their pick of prizes. All the way down to worst hand, who many times also gets a consolation prize (at my snowmobile clubs ride you get a sweatshirt, but also have to sign a toilet seat that has all of the worst pokerhand signatures on it.)