Structures are your economy buildings, ammunition and weapons will not make themselves and packets will not teleport to target destinations. Therefore you must build out a network to connect weapons and collect energy.

Collector is the most basic element of your network, it serves both as energy producing building and can make connections with all other structures and weapons.
Cost: 10 packets/9 after upgrade

Network connections: A collector can connect to any structure or weapon within 5 squares of it for vertical and horizontal lines or ~5,8 for diagonal connections( for example 5 squares horizontal and 3 squares vertical from it), the maximal connection range is <6 so while still in air a bit longer connection is possible.

Energy collection: A collector can make up to 0.18 energy each. Each green square 0.004 energy, a collector can up to cover 45 squares. Collectors placed under 45 degrees will overlap 7 squares. Collectors placed with an offset of 5 by 3(maximum connection range) will only overlap 6 squares. Placed in a horizontal or vertical line they overlap 10 squares.

Relays are used for long range connections. A relay can connect to all weapons and structures in the same way as collector however a connection with another relay can be up to 11 squares in a horizontal or vertical line or 11,7 in a diagonal line (11 horizontal and 4 vertical squares).
Cost: 20 packets/18 after upgrade

Each Storage adds 20 to players maximum energy storage.
Cost: 20 packets/18 after upgrade

Each speed node increases the speed at which packets travel along the network.
Packet speed is calculated from the following formula speed= 2 + s/2 where s is the number of speed nodes in the network. Therefore, each speed node will increase the speed of the packets by 0.5 squares/frame.
Cost: 35 packets/31 after upgrade

Reactor generates energy. Each building produces 0.3 energy.
Cost: 40 packets/36 after upgrade