The aim of the game is to combine tiles until you make just one tile that has the number 2048 on it. You can use the arrow keys to slide the tiles in the direction you want (if this isn't working, you might need to click on the game board first). To merge tiles, place two tiles with the same number next to each other and then hit the correct arrow key to push them together.
To win, you gotta try to combine the tiles smartly until you get to a tile that says 2048. Just press the arrow keys to move the tiles where you want (if it doesn't work, you might have to tap on the game board first). To combine the tiles, just put two tiles with the same number next to each other and then hit the arrow key to push them together.