Hey, look, if you're new to cooking, there's no shame. You live, you learn.
When it says bring to a boil, that means as soon as it starts to boil, reduce the heat to literally the lowest setting. The reason for this is to kick the temperature up so it starts to cook, then maintaining that cooking level with minimal additional heat. This also sterilizes your food from any gay bacteria. As a general rule, never boil protein for longer than a minute or you may as well eat your own shoes.
When it says medium-high heat, it means slightly less hot than your medium setting (4). Ignore the instruction to let the oil smoke - an easy trick is to put a small piece of onion in the pan first, crank up the heat, wait until that piece of onion sizzles, add the rest of your onions, wait a few seconds, then reduce the heat. Remember that adding ingredients to your pan always lowers the temperature - the higher you have it, the less of a problem that is. Part of the skill of cooking is having the confidence to constantly adjust the temperature according to what you can see is happening, not what the recipe tells you.
If you burn your starting ingredients, chuck them out and start again, no matter how good they smell. Onions going brown are caramalized, which means the natural sugars have oxidized in the heat and 'cooked'. If they burn, it means they've carbonized, and carbon will only lend whatever you're cooking bitterness.