Next, trial fit both panels together to make sure they mate appropriately. If one panel's chord is slightly bigger than the other, sand it to match the shorter panel. Then, sand and round the trailing edges of both to the desired taper.
The carbon fiber strip gives a fair amount of strength to the TE, while showing where the centerline of the airfoil is, so it is easy to sand and taper to.
Here, Tim and Eric sand their trailing edges.