How to make it...?

I need to make the Do-217K armoured pilot seat, it’s something like this:

The pic is from the Airwaves’ instruction sheet, and it says that the new pilot seat must be made of plasticard… I’ve never done something like that… so I need some suggestions… Thanks in advance…

well it looks to me like you use plasticard and heat form it over the backside of a pilot figure of the same scale as the airplane

Your other option is to sculpt a master for it using sculpy or something similar, and then push mould a piece of hot styrene over it (securing it in a frame before heating it).

Another possible option would be to construct the basic shape from styrene sheet, and then use filler/sanding to make the curved surfaces, sanding & filling the corners repeatedly until you’re happy with the job.