@HH420 ok well for me I would add nutrients once your cotyle leaves have died or fallen off. I may have spelled it wrong, but those are the very first leaves that pop out of your seed. The little round ones. From there, your first true set of leaves come in. After a few days, up to a week, those first little rounded leaves will yellow and die off. Those leaves are actually the plants energy source for its first couple days. So when they’re gone, the nutrients should be administered to your seedling so she can still eat and really begin to grow roots and take hold. Very low dose for first feeding! You can always give her more later but you can’t take it back out of the soil once you water it in. Well, you can with a flush, and that’s what else you asked about. So when it says flush it’s asking you to rinse your soil with water to “flush” excess nutrients from the soil. This is done to keep from nutrient build up and lock out, and also just helps your plant get better access to certain nutrients. A flush is also performed if someone is having problems, because it will basically get your soil back to being “normal”, for a lack of a better term. So you’ll flush for a day, if your pot is a 3 gallon container, flush with 9 gallons of pHed water. After your flush, wait a few days, as it takes a couple days for the soil to dry back out. Then you can administer nutrients back into your soil the next watering. You’ll get more comfortable with flushes as you do them and get experience. I hope this helps you!