Yukon is a lot like Klondike Solitaire (Classic Solitaire) except instead of having a deck of cards, all the columns are filled with cards at the beginning, so there is no deck to deal from. Also, in Klondike you need to alternate colors where in Yukon, you only need to alternate Suits. So in Yukon, you could place a Diamond on top of a Heart if you would like, where in Klondike you would have to place a black card on top of a red one. In Yukon, the only card you couldn't place on top of a Diamond is another Diamond.
Like in Klondike you're trying to build down the columns, and build up the foundations by suit. Also like in Klondike, you win the game if you can move all the cards into the foundations having built them up to the Kings of each suit.