Can you just teach me about decimals?

No.  There's a reason why they take weeks or months to teach it in school.
The reason is because that's what it takes.  You need to hear it a little at a
time, and practice it a little at a time, in order to learn it.  If you could learn it
with a 5-minutes explanation, then that's the way they would teach it in school.
There are a few people who can learn it that way, but not many.