Every match level has an objective. This objective can be singular or include many objectives. 

These objectives can be seen at the beginning of the level and on the left side of the screen as you play the level.

Match three or more tokens of the same color to create matches. Complete matches to progress closer and closer to completing the level objective.

There's a number of various obstacles that make all the different levels more challenging.
Usually you have a limited number of moves for each level, though if you run out of moves you can buy more with coins.

Making matches of 4 or more tokens creates unique Special Bomb tokens which can help you achieve your goal.

Combine Special Bomb tokens to produce a greater effect and remove more tokens.