The first person to define the controls was William Hartnell, the first actor to play The Doctor. He took it on himself to come up with specific moves with specific controls to do things on the set. He believed it was important, as he believed it was a detail "the children" (AKA the audience) would pick up on.
That's become a tradition on the show - as the console design changes, certain buttons and widgets are assigned specific purposes. That's become all the more detailed as the show has gone on.
The six-sided design of the console was simply an aesthetic design choice. But as they were working on the 2005 series return, one of the set designers (see video in other answer) remarked to Russell T Davies that the console looked like it was designed to be piloted by six people. It made no sense for the console to be in a circle like that if one person was to be controlling everything.
RTD folded that into the new show - The Doctor's piloting style got a lot more chaotic and physical, racing around from panel to panel. And in Journey's End, they added that explanation into continuity officially, having all of The Doctor's friends take a console, and with a full crew, The TARDIS was able to tow the Earth back to its original position in space.
As before, specific panels and controls have very specific uses. For example, the Helmic Regulator, which has gotten a few callouts over the years, now resembles a bicycle pump.
Nowadays, the TARDIS console on the set has a user’s manual. The controls on each panel are specifically named, and each has a specific function. Matt Smith was given the manual and had to learn it. He had to learn a precise series of actions to launch or pilot the capsule “properly”. He wasn't just making it up. Presumably this was true for Capaldi and will be true for Jodie Whitaker
We can only pray we never learn the true use of the "Smurd" button.