In total there are 6 challenge areas which vary in difficulty. Some are easier than others, but they require some patience and practice. I recommend that you do one or two runs through the arenas to learn where everything is, and how to navigate the areas. Once you're ready, you will need to make your way through the arena of choice as quickly as possible. To earn the high scores you will need to make sure you take no damage, hit as many point orbs as possible and finish with a time. If you collect all the orbs but cross the finish line without a time, you won't hit the four star rating.
It's possible to take some damage is illustrated in the video, but as long as you don't keep repeating the same mistake and lose multiple groups of 100 points, you get get away with taking one or two hits. If you do happen to hit a section with fire and end up catching on fire yourself. Use it to your advantage and speed through the rest of the fire traps. You won't take extra damage or lose more point unless you stand around for long periods of time.
I highly recommend that you obtain all the ability upgrades before you attempt these as some of the extra abilities improve your chances of completing with ease.
You can find the areas in the following areas:
The Sorrowing Meadow
Challenge Area Map: