I started level 11 but I can't seem to complete this objective. It says to fill power meter 5x in one run so I've died over and over and nothing. Please help. Thank you.
Just collect coins until your power meter (upper left-hand corner) lights up, double-tap the screen to activate your chosen ability, and repeat that four more times in one run.
You can make this slightly easier by choosing an ability that does not block you from filling your power meter while it is active. Those would be Coin Bonus, Score Bonus, and Gem Bonus.