Make sure that you're connected to the internet then launch Minion Rush. On the Main Screen, tap "friends". On the upper right corner, there should be 2 icons. Tap the one on the right, the trophy icon with the clock. It should show you the weekly contest. On that screen, there's a blue circle with a trophy with a question mark. Tap that. It would show you a "weekly goals rewards". Right now it's "jump over 150 obstacles". Do that, then go back to that screen to claim the reward. That would complete the mission.