Hello @dlwofls119 and welcome to the forum!
Digital colors don’t mix like real world colors, for Krita there are a few attempts to bring better mixing, but currently there are only test builds as a proof of concept.
You can test these outdated test-builds here if you are on Linux or Windows, it may be interesting to test but not worth the effort because it is not developed further:
But you don’t need that to paint gorgeous works, as you can check out in our gallery! Only your ability and will is needed to achieve what you can see in the better pictures there, because not everyone posting pictures here is on the same level, like in the real world.
Michelist