That's a really bad advice to give beginners. If you're lucky, you'll guess right the first time, and end up with a good dish. And then you'll use that.
If you're unlucky — and the more inexperienced you are the more unlucky you are — then you'll guess wrong, and your dish will be at best okay, and at worst inedible.
A few failed experiments like this, and you'll hate cooking, or approach cooking with fear. Recipes have to be very precise, because recipes are aimed at people who are new: new to cooking or new to the dish.
If you're unlucky — and the more inexperienced you are the more unlucky you are — then you'll guess wrong, and your dish will be at best okay, and at worst inedible.
A few failed experiments like this, and you'll hate cooking, or approach cooking with fear. Recipes have to be very precise, because recipes are aimed at people who are new: new to cooking or new to the dish.