On this site, waterproof means the stainless steel bracelets. The cuffs and bangles. They can go in the shower. A ring, a necklace, an earring, or a watch is not waterproof, even when the metal is steel.
Leather straps are a separate problem. Water marks them. Steel chain bracelets are the pieces that can get wet.
The bracelets are in waterproof jewellery. For the routine, see what to take off in the shower.