Flat feet help?

So, my four-year-old just got hit with a diagnosis of pes planus, which apparently happened because some orthopedic specialist swung by his preschool for foot screenings and decided that was his lot in life, though none of the teachers there can actually wrap their heads around what that even means in plain English...
The big recommendation they handed me was to make sure he’s wearing "proper footwear," but honestly, he’s already wearing the standard anatomical stuff you'd find at a place like Stride Rite or even Target, so I'm feeling a bit lost here.
I could really use someone to break this down for me, if anyone actually knows what's going on.

man, seriously 😬

it would have taken you literally one second of basic Googling to figure that out—lazy...

Or, if you want to be more technical 😁 😁, flat feet...

So, flat feet aren't exactly rare in kids. Most of the time, it’s just a mild thing that fixes itself as they grow, and you won't have much to worry about down the road.

Getting decent shoes is key, but honestly, some playtime exercises go a long way too. I remember my nephew used to do this thing where he'd try to pick up tiny Lego pieces or pencils with his toes—looked ridiculous, but it worked. You could also try having him walk on his tiptoes, then on his heels, or just doing some ankle circles. If you frame it as a game, they usually don't even realize they're "working out."