For the construction of the sidewalls or sides of the cockpit, I first started with the thick sidebar from the front/side MIP runs to the back of the cockpit.

This bar is located between the Dv Window armrest/Chart holder’ and the ‘sidewalls’.

Images and info of this sidebar is to be found at the following link :
http://www.flightdeck737.be/hardware/platform/zijpanelen/constructie/