You start with 7 columns of cards. The first column has 1 card, the second has 2, and so on up to 7. Only the top card in each column is face-up. The rest are face-down. The 24 leftover cards go to the stock pile in the top left corner.
Move all 52 cards to the 4 foundation piles in the top right. Each pile is built by suit, starting with the Ace and going up: A, 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K.
Click the stock pile in the top left to flip one card to the waste pile next to it. You can play the top card of the waste pile. When the stock runs out, click it again to flip the whole waste pile back over and start again.
You win when all 52 cards are stacked on the four foundation piles. Klondike is not always winnable, but with good planning you can win most games. Take your time!
Always check the color before you move a card. It must go on a card of the opposite color. This is the most important rule. Getting this wrong early can block your whole game.
Try to uncover face-down cards as fast as you can. The more cards you can see, the more moves you have to work with. Look for the shortest columns first.
An empty column is very useful. You can use it to move cards around and free up space. Only put a King there if you have a plan. Don't fill it up right away just because you can.
Try to keep your four foundation piles close in rank. If one pile is way ahead of the others, you may not be able to play the low cards you need.
Try to make all the moves you can before clicking the stock pile. Drawing too fast can bury cards you need. Look at the whole board before you draw.