Short Japanese Culture Questions

What is the deal with the criss-cross wooden-slatted platforms next to lockers or cubby-holes for storing shoes and packages, like you see in school anime scenes?

Are those ‘do not step on with your outdoor shoes’ zones? If so, do you need to do a sort of balancing act on one foot while you remove the shoe from the other foot, and step on the wooden platform in your socks while you put that shoe into the cubby hole, then balance on that foot while removing the other shoe, or something else? How do you do the reverse, to put your outdoor shoes back on? Isn’t there still a problem where some floor zones are for both indoor and outdoor shoes (or indoor socks)?

The last time I was in Japan (in 2018), I visited the ‘Herring Mansion’ in Otaru, Hokkaido (made famous in the Golden Kamuy anime), and must have done it incorrectly because I got scolded by the attendant (who also remarked in English that it was a silly Japanese custom, after all).