Just ask them how they're applying it, like which colours are going where and with which brush if they don't say but they probably will.

Let them know you're unsure of which foundation is best. Just decide if you want something matte, dewy, sheer, medium, full coverage and whether your skin is oily, dry, normal and with that they'll be able to decide what's best for you.

As for blush, just figure out what colour family you want the blush in, like warm or cool or pinkish, peachy, plummy etc. and they'll be able to recommend something.

I wouldn't worry too much about this. It's supposed to be fun.

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NC15, light brown hair, blue eyes