Networks are what you need to play the game, connect any collector to Odin City, then it will be build. Placing a structure nowhere near Odin City will just sit there until it is connected to your network.
To improve your game, build speeds and reactors, reactors produce energy, speeds make packets go faster!
If you build too much units, you will 'starve' your network. Starvation is when you build too many units that your City just carnt handle!