I can tell you that when you go to SP recipes and to a certain recipe, you can see at the top there's an orange bar with different options and one of them is the recipe calculator. That's where you can put your own recipe in. I've put in recipes from Cooking Light and other recipes all the time. You first put your ingredient in at what the whole amount is for the whole recipe. Say, you want whole wheat flour and if the recipe calls for 1-1/2 cups that's what you'll put in, and then for your next ingredient, you'll have to click on "add ingredient" again. With each ingredient that you add, a list of items will come up that are like your ingredient and then you choose from that list. You log all you total ingredients and then it'll take you to a site where you'll see your whole recipe listed and then below that, they ask you to put your ingredients in another spot just as you would write it on a recipe card. Like 1-1/2 cups whole wheat flour, etc. Because with the first list of ingredients, it won't make it quite so clear. Like it'll be in ounces, or pounds, and you'll have to convert where they give you converting scale option too. The rest of it, you will just follow what they ask. Pretty simple but I sure had trouble to begin with. Good luck! I can't tell you about adding to your 28-day challenge.