Here's how it goes, you do ten minutes worth of planks a day for a week. They can be standard planks or elbow planks (i would recommend elbow planks because they're more challenging). You don't have to do the all at once, you can disperse them throughout the day. You can do 30 second Planks or 1 minute Whatever you feel comfortable with just remember the time added up musty be ten minutes. I personally did ten 1 minute elbow planks and it does get difficult but that's why they call its a challenge. Trust me you will get results if you do it religiously.
My personal record (you could believe me or not) is 30 min full plank at once. It is my second because the first was 22 min and 22 sec. I doubt that I will ever do it again, but I did and that is only matter. Just saying :)
My freshman year in highschool I would be done after a 30 second One
I'm so readyy! Woooo!