Once you click play, a new window will open. You will need to sign up for an account on this website (or login to that site if you already have an account).
Then, after you complete the signup/login process, scroll to the top of the new window and click on the games tab. If you do not see the games tab, please increase your window size. You can play games to increase your "mining power" on that site to earn BTC, ETH, or DOGE (you can choose how much to earn on the home page of the popup under "My power").
As long as you keep playing games, you will be able to claim in-game "stakes" on SOL Faucet for every five minutes you play the games. Whenever a green banner appears at the top of the SOL Faucet window, click on it to claim the in-game "stakes". This in-game "stake" can be used to earn extra Solana rewards, see more details on the Games tab of SOL Faucet.