So I'm going to demonstrate how to do a 2-point plank for you, which is a progression from a normal plank. So I would not do this unless I've mastered a normal plank either on my forearms or on my hands. So what you're going to do is you're going to start out on your hands.
Lift your knees off the ground. You want to make sure your hands are directly under your shoulder, your alignment is good, you're engaging your core, your pelvis is tucked under. What you're going to do is you're going to lift one leg and the opposite arm. You're going to hold this, or you can count repetitions: do 5 on each side, do 10 on each side. Or you can just hold this for 30 seconds. When that's done, you can switch. Hold for 30 seconds. You also have the option of doing this on your forearms as well.
So that would look like again making sure the alignment is good. Lifting one leg up and reaching out with the opposite arm. Again, either concentrating on reps or timed interval sets. And that's how you do a 2-point plank.