New pc build won’t turn on

First time building a pc. Everything is brand new besides the motherboard, it’s a friends old mb, msi z170a gaming pro carbon. I quadruple checked that everything is plugged in correctly and it won’t turn on. What would be the cause? I’m new to this, this is my first time doing this, any friendly advice and tips would help. This is everything I have for my set up:

SAMA 2851 atx midtower case

Corsair rme 1000 psu

Nzxt kraken 360 plus

Zatoc gaming GeForce rtx 3060

Msi z170a gaming pro carbon