So as some of you may know, my original console was made from cardboard boxes, but I decided to rebuild it a few weeks ago. But this time I'm using hardboard. But I need help:
How would I mount the panels onto the console? Would I need to build support struts between each of the panels?

Kind regards, The14thDr

You'd probably be better to use MDF (medium density fibreboard) as it's less prone to sagging. If you use hardboard, you'll definitely have to re-inforce it to take the weight of whatever controls you intend to mount on the panels.
Tony

Well, the panels are only 40cm across the bottom, 18cm across the top and 26cm top to bottom. And the controls will only be cardboard and paper maché. Would that still make the panels sag? My dad says that if the panels are small enough, they won't sag as much.

Kind regards, The14thDr

EDIT: Just updated the measurements for the panels. (I'll update my build diary later)

I would suspect if the console will only be the dimensions you have stated then card and papier mache controls shouldn't make it sag.

I'd suggest using furring strips to reinforce the plinth and frame the consoles if they're not framed already. Drill pilot holes in the console frames for the panels and slightly larger holes to fit the screw shank. Then get some brass dome-headed screws and small washers to hold the panels in place, let them stand out a bit.