I didn't print out the details of the plank challenge but basicaly you start out with a 20 second plank for a couple of days. No rules on how many you do. You increase your time by 10 to 15 seconds every few days until you work up to a 2 minute plank at the end of 28 days. Not sure if I will ever make the 2 minute one. I did 2 30 second ones in the morning and 2 more in the evening. I have no abdominal muscles so I will have to take it slowly. It said to do them how eer you can that you need to make sure you keep your body straight. I do mine on my elbows mostly because it bothers my wrists but you don't work your arms as well that way. A plank is supposed to work so many muscles at once.
WOw Leann you have a lot going on. I will pray for things to get better.