How do I properly attach the windscreen to avoid breakage?

It is important to put bolts in the center two holes first (loosely), then the two holes beside those, etc, until you've worked your way around the screen. Do not use any type of wrench; hand tighten only. Gradually tighten the centermost bolts a bit, then the next outer pair, and the next, until each pair of bolts is snug but not tight; the screen needs some slack to flex. If you tighten the bolts too quickly, in the wrong order, or too tightly, you risk cracking the screen.