Mac is a high line cosmetic and that specific brand tends to cause breakouts. To get Mac, Clinique, or Sephora you need to go to Macy's. They sell it there.
Blush, goes on your cheek bones. Don't mix that with concealer. You want to choose a blush that's more of a bronzing color. You want it close to your skin color (a little darker) to high light those features. You can YouTube videos on your face shape on how to highlight your features.
Concealer is meant to cover up blemishes and wrinkles. It's a thicker substance than foundation. Foundation makes your face not look greasy and adds a sort of nice look to it (don't over do it) buy one that will blend in with your skin color. You can test it by taking a bit on your finger (use concealer to test this and then buy the foundation with the same pigmentation) and rub it into the underside or your forearm. The fleshy part near your elbow. Your palm should be face up. If it blends to wear you can't see it anymore that's the color you need.
I suggest you don't buy concealer. It can look caked on and is meant for older people anyway.
When using foundation just lightly brush your face with it and that's it.
Don't mix blush and the foundation. You'll look weird honestly and caking it on a zit won't help.
If you want a product that won't cause breakouts you can go high end and get Clinique or sephora or you can buy neutrogena or any mineral base powder (neutrogena and Rimmel work best, others such as L'oreal and CoverGirl get mixed reviews)
You want to accent your feature and keep a natural look.