In order of what goes on your face:
- Primer, there are many different primers for different skin problems but the main goal for most primers is to boost makeup longevity and to create a smooth canvas. Try the Younique Glorious Face & Eye Primer to create a flawless canvas as it evens out the skin's texture, and primes and prepares the skin for premium application of mineral makeup.
- Concealer and Foundation, I don't think it really matters which order for these two if you are just covering dark circles. But if you have spots I would apply the foundation first and then use the concealer to cover any spots still showing.
- Setting powder, not to be confused with powder foundation, sets your makeup to boost longevity and to decrease shine. I recommend using a flat top powder brush to apply this, pat do not brush across foundation as it will move it and you will end up with uneven patches.