How do you bathe your baby?

My baby is 7 weeks old now, have been bathing her with half a pump of the cetaphil shampoo/soap into the bath water in baby tub as taught by confinement nanny. And don’t need to wash off. Wondering when can put more of the soap and when to put the soap/shampoo like how we bathe as adults..? Thanks!#firsttimemom #advicepls