To start up the game, players simply need to hit the spacebar, which will make the dinosaur run and hop over the cactuses that come into its way. If you're playing on your mobile device, you can just tap your thumb. Jumping over cactuses earns points, and failing to clear the jump gives players the dreaded Game over. 

The simplest way to play the game online is by visiting this URL: chrome://dino/. Just access that link and voil, there's your little dino and "no internet" message.