You play as the final survivors in the aftermath of the war between man and machines, and you've found refuge on a distant, hostile planet.
It's up to you to take control to hold off the hordes of wild beasts attacking your defenses, as you try to regain your former strength.
In Brace the Swarm you are give control of a base and the ability to construct new structures and turrets.
As you keep playing waves of enemies will spawn around your base, and it is up to you to keep your base safe. You will likely want to expand outwards on the map as soon as you are able to, so that you can harvest the resources necessary to stave off the endless swarm. To do so you can build Extractors above crystal mines and resource harvesting should start automatically.
In Brace the Swarm, keeping your structures lit and powered is vital. You do so by constructing Batteries and Illuminators throughout your base. When a light is created, it will automatically connect with any other light or structure within its range. These will have to reach every structure that you construct, so you have to be smart with how you're placing them. If one critical light is knocked out, it can plunge your entire base into darkness.
To keep your structures powered, it is enough to have a Battery (or a light connected to a Battery) nearby. The bar at the bottom, above your turrets, is your power bar. This tracks the main power availability of your base. If all your power is on the same network, this will let you know when you're running low. However, keep in mind it will only track your largest network, so any smaller independent power networks you might create will have to be kept special care of. Look out for the red "unpowered" icon above structures to see if they are not getting enough power.