Here's how it works:
When the game starts one color will Mep.
Click that Mep.
You'll see the Mep smile meaning you repeated it correctly.
Then the first Mep will Mep again followed by another Mep.
Click the two Meps in sequence.
You'll see the smiley face.
Then three then four... etc.. just follow the sequence.
Every four levels completed you'll see a little cartoon.
If you get the sequence wrong you'll see the sad Mep. And then you have to start over.
Don't feel bad if you have a hard time figuring it out. My friend Megan who is the smartest person I know was stumped at first.