Hi, you will have an easy time decoding scales given to you on websites,
if you 1st familiarize yourself with this chart.
I have heard all kind of nonsense from musicians who had an incomplete understanding of these terms. The article explains what is meant by this stuff,
0 Perfect Unison
1 Minor second
2 Major second
3 Minor third
4 Major third
5 Perfect fourth
6 Diminished fifth
7 Perfect fifth
8 Minor sixth
9 Major sixth
10 Minor seventh
11 Major seventh
12 Perfect octave
These are the basic names, the article explains about the alternate names, for example M7 also being sometimes called m8, and etc.
Also, a rule says that if a chord has a 7th and a 2nd both, that you should call the 2nd the 9th rather than 2nd. Some musicians apply this rule even if a 7th is not included. The same with 10th, 16th, and basically any interval greater than 7 you just subtract 7 and there you are.
The article explains it, interval means distance between two notes, and in most cases and for the purposes of this chart an interval refers to distance between a note and the root.
Dont spend alot of time with theory, I recommend, at first, you want to get alot of practice under your belt then study theory, or you may not feel right. It takes 1000s of hours of practice for any of this to even be close to relevant to a musician. Go for 10,000 hours - thats 20 hours a week times 10 years.