There are two approaches to understanding the minor scale. Both are important.
First, the minor scale is like the major scale: It’s made of five whole-steps and two half-steps. However, the steps are arranged differently. It can be written like this, where “^” means half-step:
1 2^3 4 5^6 7 1
The half steps in a minor scale fall between 2 and 3, and 5 and 6 (Remember: in a major scale they’re between 3 and 4, and 7 and 1).
The second way to conceive of the minor scale is by taking a major scale and flatting (aka, lowering by a half-step) the 3rd, 6th, and 7th notes. We will write these from now on as b3, b6, and b7. This is important for reasons I will go into in a later post. You can think of a minor scale relative to a major scale like this:
Major: 1 2 3^4 5 6 7^1
Minor scale: 1 2^b3 4 5^b6 b7 1
Notice that by flatting the third note of the scale, you move it farther from 4 and closer to 2. This causes the half-step to move from between 3 and 4 to between 2 and 3. The same thing happens when you shift both 6 and 7 down a half-step.
TL;DR: A minor scale is made of 5 whole-steps and 2 half-steps. The half-steps fall between 2 and 3, and between 5 and 6. You can get a minor scale by flatting the 3rd, 6th, and 7th notes of a major scale. It can be written like this, where “^” means half-step: 1 2^b3 4 5^b6 b7 1.