Lots of these exercises are on my plank page, plank.htm
You can work your way up to this "challenge". Some ideas:
Cut the time in half. Do each plank for 15 seconds instead of 30.
Cut the challenge in half. Just do the six planks that you like the best.
Take a breather. Do two plank exercises (1 min) and take a rest (1 min) in between.
Then, the next two planks...and rest.
This workout becomes a 12 min challenge that's a little more manageable.