Scrambled eggs come out different every time for people who have made them for years. The variable is the heat under the pan, and it's the one thing every recipe assumes you already know how to judge.
Your first day
Eggs are the fastest way to see what heat does: on high heat they go from raw to rubbery in under a minute, so a mistake shows while you can still learn from it. Starting takes about ten minutes. Crack two eggs into a bowl and whisk until uniform. Put about a teaspoon of butter in the pan before turning on the heat, since an empty nonstick pan overheats and damages its coating, and set it on low, low enough that the butter melts slowly instead of foaming right away, that's the actual test for whether the heat is low enough. Pour the eggs in and stir slowly and constantly with a rubber spatula or wooden spoon, never metal on a nonstick pan, scraping the bottom the whole time, listening for a gentle sizzle rather than an aggressive one.
Pull the pan off the heat while the eggs still look glossy and slightly wet. They'll keep cooking from the pan's residual heat for another few seconds. If you're serving anyone pregnant, elderly, very young or unwell, cook them until no liquid egg remains.
Most people turn the heat up because low heat feels like it's taking forever. Don't. High heat turns eggs rubbery and grey in under a minute, and there's no fixing it once it happens.
You're done when the eggs form soft, creamy curds. If they came out dry or grey, the heat was too high, and that is what to change next time.
The thing most people miss
Eggs come out different every time because a burner setting means something different on every stove and in every pan, so a dial number isn't the measure. Sound and sight are: butter that melts without foaming, a gentle sizzle, eggs that look glossy and slightly wet when you take them off the heat.
Learning to read those signs is what carries over to every other dish, because every recipe that says medium heat is asking you to judge heat the same way.
A misconception worth correcting
Turning up the heat doesn't make eggs cook better, it just makes them cook unevenly. The outside sets and toughens long before the inside catches up, which is the rubbery texture most people blame on the eggs themselves rather than the burner.
Knife work is the next place this pays off. Vegetables cut to an even size cook evenly for the same reason low heat cooks eggs evenly: everything reaches done at the same time.