You have several boosters to use, to use a booster just click or tap it and press on the coins. It costs coins to buy a booster. You can earn coins in the game. The boosters:
The game has a total of 100 levels. You can unloc k new levels by getting stars. Finish the game in a certain amount of bubbles to earn 1 to 3 stars. In the right top corner you see how many babies you have to rescue. You start with 5 lives and can get new lives by earning them.