Newbie perspective-

Buy the pedals from amazon or whatever, I paid $53 for mine, a standard 15mm wrench DOES NOT fit on these pedals unless you grind it. Buy a $10 park tool wrench from amazon.

Try on the shoes in the store, and either buy them there or buy them online.

Put the cleats 1/4" behind the ball of your foot, if youre anything like me angle them slightly outward (looking down at feet \ / )

Set pedals to minimum tension with an allen key.

Go for a ride and fall over when trying to move your unclipped foot.

Ride again and adjust your cleat angle until they feel "natural" and like theyre not twisting your foot.