You should always shampoo before masking, but afterwards condition your hair. The shampoo will loosen up the cuticles on your strands, allowing them to absorb more nutrients from the treatment. After that, rinse the hair mask in the shower with cold water for the recommended amount of time. You should use cold water to rinse out the hair mask instead of warm water since this will help seal your hair cuticles, reduce flyaways, and keep your hair moisturized.