How do you expect tourists, including people coming from other regions of Japan, to familiarize themselves with the layout?

I've been in Shinjuku few times, I've always got lost.

Found a "hack" where I would go upstairs to the mall and then go down closer to the spot I need.

Shinjuku is way too massive (and now has plenty of diversions due to work om the station itself) to be understood easily by a tourist.