How can I exchange parts for thermal goggles?

In order to get parts to exchange for the thermal goggles, you need to wait for the events to take place like the Sharpshooter event. So far, that's the only one I've noticed since I've been playing. And I only see it in PVP matches.

What will happen is you will start seeing glowing targets in the sniper arenas. Hitting them will give you parts. The parts look like hardware bolts that you screw into nuts. They have Gold, Silver and Bronze parts. Having these will allow you to exchange them for different chests that will sometimes have the Accessory parts you need to build stuff like shields and thermal goggles. That's about all I know for now.