Klondike Solitaire (Draw One)
The goal of Klondike is to move all cards into the 4 foundation piles in the top right. Each foundation may only hold ordered cards of the same suit, from Ace (lowest) to King (highest).
The 7 "tableaux" piles at the bottom accept cards stacked by alternating colors (red/black), and are ordered from King (highest) to Ace (lowest). You may move cards between tableau piles, or to a foundation from the tableaux.
The top left face-down pile of cards is your deck. Click on the deck to draw a card to the "waste" pile; from there it may be dragged to a foundation or tableau pile. Once the deck is empty, you may recycle the waste pile by clicking the empty deck section.
For more information, see this wikipedia article.