"Use your arrow keys to move the tiles" ? How about a few more words about rules. How do you pick which tile you want to move? And btw, when I tried, two til

"Use your arrow keys to move the tiles" ? How about a few more words about rules. How do you pick which tile you want to move? And btw, when I tried, two tiles with same numbers were NOT merging most of the time. Other times it seemed that the entire row was moving. Then again, I could not figure out how to select a tile to move. Mouse seemed to work but only sometimes. Perhaps accidentally... Too buggy or just big time lag.., or just big time lag..