Recipes, as far as they are picture-less instructions without sophisticated creative content, usually do not fall under copyright law and you can use them without any restrictions. I would say my recipes are pretty much uncreative instructions and therefore you can use them however you like.
Sourdough Starter: mix equal weight of water and rye flour (in cups, use half the amount for water, so 1 cup flour ½ cup water), then follow any feeding cycle to ripen the starter. Really, the only difference is that I always use rye. When mixing the dough by hand (with a spoon), rye is much easier to incorporate because with a lower gluten amount it doesn’t stick to itself.
Sourdough bread proofing: Not enough time for a full rise/stretch+fold plus bulk ferment cycle? But under-proofed bread if using without bulk ferment? You can totally do the initial rise and stretch+fold/coilfold of about 4 h on one day, place dough into fridge, and continue with a bulk ferment for some hours on the next day. I usually let it sit in the oven with light on (the light bulb emits a bit of heat) for about 6 hours (until very delicate and wiggly), with one coilfold after the first hour to distribute the warmth. You can then shape it, and let it sit in the fridge again until baking the next evening (or bake it right away or only cool it for an hour or so for better handling). Over-proofing sourdough bread is actually not that easy unless you use huge amounts of ripe starter. If you have time for proof and ferment on one day: great. If you don’t, don’t worry about interrupting it with a night and day in the fridge.
Cooking and Baking is no witchcraft. And while it is chemistry and physics and biology, you certainly don’t need a STEM degree. For most things, it is not necessary to get the amounts exactly right, unless you are preparing an industrial product. When using recipes online or in a book, try to stick to the amounts as closely as reasonable. 227 g of starter but you added 220 or 230? Doesn’t matter. That’s why cups and spoons are still useful. They make cooking and baking more accessible. You don’t need to remember all these odd numbers, but 1 and 2 and ½ instead. As long as the ratio is right, you’ll likely have no problem except maybe an overflowing cake pan if you exceeded the amounts by a lot. And if you own neither a scale nor measuring cups, then a regular (small) cup and regular spoons will do. You can also totally substitute ingredients, or add ingredients. It helps to know what you are doing, substituting whole wheat needs a tad more water for example, adding non-soaked seeds also definitely needs extra water. But none of this is some high science and you can usually find out how to change the recipe to your wishes by just doing a quick online search. If you want to bake as a total beginner without any baking experience, stick to the recipe to build your courage and knowledge. But if you feel like you know what you are doing - just try it. Your life does not depend on that one bread.
And even where all of this is relevant, the important part is always the ratio between two or more ingredients and temperature/duration based on final weight, never the actual weight of an ingredient. The only really difficult thing I have yet encountered is actual traditional Angel Cake and similar recipes. Leavening a dough only with egg is indeed more difficult. Maybe just don’t make those.
Baking time adjustments: Most recipes online focus on small breads, even what is called a “miche” rarely exceeds 1 kg dough weight (pre-bake). An overview of baking time for larger loaves (wheat, spelt, or similar; for larger content of rye add 5 minutes), for baking times exceeding 40 minutes, turn heat to 350-390 F degrees:
After baking, wait at least 2 hours before slicing! If you are using a higher rye content than just rye starter, add an hour or so. If it is more than 50% rye, add many more hours (best over night)!
The Common Sourdough Bread
Pasta with Red Lentil Sauce
Smoked Paprika Soup
Two Loaves Sourdough
Seitan Cold Cut
Chewy Pancakes with starter
Soy Milk Ramen Broth
Garlic Soy Sauce Pasta
Pumpkin Seed Bread