Planets
Structures
Without buildings, planets are little more than balls of rock orbiting stars. By using the Building Menu, players can build, demolish, and cancel the structures that make their planet great. Although multiple buildings may be queued to be built, only one building may be built at a time.
The characteristics of the structures you can build are described in List of Structures.
Demolish
Buildings can only be demolished after they are built. Demolishing buildings requires half the number of turns as constructing the building, unless structures decreasing travel time which requires same number of turns as to build them. The orbital or ground space used by the building are returned to the planet; resources are not.
Note: You cannot demolish while constructing
Cancel
Buildings can be cancelled before they are completely built. All resources used in the construction of the building are returned to the planet, as well as any orbital or ground space used by the building.
Ship Yard
The Ship Yard is where players can build ships for their fleets.
A Ship Yard is required to produce ships. You don't need a Ship Yard to create fleets if there are already ships on your planet. At game start, your home planet already contains an Outpost Ship that you can use to colonize another planet.
Only one type of ship can be produced at any one time. Any number of ships can be produced at any one time. Here is the List of Ships you can produce.
Building multiple ships does not add additional time to the default production time for the type of vessel being produced.
Create a fleet
Once some ships are built, or if you already have ships on your planet, you need to create a fleet to use these ships.
Type a fleet name and click on "Create Fleet". Then you see the fleet transfer page.
Barracks
In order to train soldiers for invading or defending you will need to build a barracks on a planet.
The barracks requires a light weapons factory to be built first.
Once built a link becomes active on that planet to go to the barracks screen.
Soldiers are used to invade hostile planets during the game. Soldiers are also protecting your own planets from Invasion.
Converter
Communications/Radar
You need first to build a Comms Satellite.
It lets you see all the fleets moving into the same system as the planet where you built it. They are visible in the Radar tab.
You can also see them in your planet's Communication Menu, which also gives you the ability to scan planets.
Scanning
You need first to build a Comms Satellite.
Your planet's Communication Menu gives you the ability to scan planets:
Resource Scan
The Resource Scan lists detailed planet resource and space information. It includes the planets abundance percentages of resources and the planets available land and orbital space.
( 
500 per scan.)
Surface Scan
The Surface Scan lists all the information provided in the Resource Scan in addition to all buildings, Colonists and Soldiers currently stationed on the planet. These informations are useful if you want to invade a planet.
( 2000 per scan.)
Fleet Scan
The Fleet Scan lists all ships currently orbiting the planet or going to the planet. These informations are useful for space combat.
( 5000 per scan.)