The most important scales out of these are the Major scale and the Natural Minor scale.You can make a lot of great music with just that. Understanding these scales will help you understand many other concepts in music theory.
Before we dive into the rabbit hole you have to know a few terms.
Semi tone(s): The semi tone is the smallest interval on the piano. It’s the closest note to another note.AKA half step.
Tone(t): Tone is two semi tones. AKA whole step.
Sharp: Higher in pitch by one semi tone.
Flat: Lower in pitch by one semi tone.
Interval: Difference in pitch between two notes.