Speed outs are your friend:
https://www.amazon.com/SpeedOut-Damaged-Screw-Extractor-Bolt/dp/B00IRL3WP4
Order a replacement screw or three at the same time, since you will be ruining the screw. It happens to all of us, its not a big deal. In the future just remember that none of the screws require any kind of force when you are putting them in. I usually operate under the guide that finger tight is best. That's the force I can apply with 2 fingers. If I'm cranking down on something, it usually means that I'm doing it wrong.
Luckily, this is a cheap and easy fix.