How do you play backpacker card game?

It seems you're asking about a card game called "Backpacker." Unfortunately, there isn't a widely known card game with that name. It's possible you're thinking of a game with a similar name or a game played specifically in a certain region or group.

To help me figure out the game you're asking about, could you please provide some more details? For example:

* Where did you hear about this game? (From friends, online, a specific website, etc.)

* What is the general theme of the game? (Travel, adventure, collecting items, etc.)

* How many players are involved?

* Do you remember any specific cards or gameplay elements?

With more information, I can better understand which game you're referring to and provide you with instructions.