The game has different groups of episodes, with 10 levels each. The higher the level, the more difficult it will be.
To see the different Episodes, tap on the one that is available in the game's main menu. For example, if you are on Episode 1, you will see 'The Workshop - I' and, once you select it, you will be able to choose from the different available episodes.
Within each episode, you will be able to see your best word and the new words you've learnt in the game.