The key thing is to notice that ∠CED is the same when flat and when folded, as when folded you are folding along the line ED. Hence the angle is constant, just in a vertical plane upright rather than horizontal on the paper. The same goes for ∠BDF as you are folding along the line FD. I recommend you cut out a triangle like I did to help visualise if you still have trouble :)

The bottom of my answer got cropped out, but it is just angles in a quadrilateral AEDF add up to 360°, so you do 360 - (110 + 68 + 60)