Your going to need to remove pretty much all of the trunk liner, to include:
Trunk floor mat and the cover over the spare tire.
Rear floor finish plate. This is the vertical trunk liner at the rear of the trunk and below the trunk opening. It extends the width of the trunk and vertically from the trunk floor to the trunk opening.
Left and right trim covers (liners). These cover the left and right sides of the trunk.
With the above removed. The L/R torsion bars will be exposed.
The following is to remove a complete bar. Since the bar is broken you can reverse the procedure to to install the replacement bar.
Pull out the section of bar that engages a hole in the side of the chassis. There will be more then one hole to allow bar force adjustment. The middle hole is the standard setting.
Remove the other end of the bar from the roof side panel.
There are two different bars that can be used. If green paint on bar its for a trunk lid without spoiler. If yellow paint with spoiler.
Would assume left and right bars use the same location of adjustment hole.
Check trunk operation. If needing more or less lid opening force adjust bar hole setting as needing.