For anyone that doesn’t know the basics of the Japanese bathing:
In a home the bathroom lay out is usually a sink and a place to get unchanged, then there’s the showering area and next to it the bath. Also in public baths there is a changing area, washing area and the bathing area. The toilet is usually in a separate room on its own.
Always wash yourself before entering the bath in the shower area. The bath is a place for relaxing, not cleaning. This applies at public baths and home since traditionally the whole family would bath in the same water.