How the Sub-Sectors and Systems work
The setting is based in a region of space known as the Australis Ultima Sector, a frontier sector within the southern boundaries of the Ultima Segementum bordering the Eastern Fringe. The Sector is split into a number of Sub-Sectors with a small description of each, representing different stages of expansion during the Great Crusade, for example the Helix Cluster was only just being explored at the onset of the Heresy and so is largely feral, full of Orks and other Xenos forces along with the occasional human settlement, meanwhile Hawcinus Sub-Sector is further Coreward and so represents well established Imperial Systems with stable worlds.
Within each Sub-Sector there will be Systems made up of planets and other major locations. Like the Sub-Sector within the Sector map, each Sub-Sector can be made up of a multitude of Systems. These Systems can be used for a variety of purposes, the first being the target of the ongoing Global Heresy; every three months a single System will be selected and all players around the world are able to submit their Battle and Skirmish Reports against the planets within that System, at the end of the three months one faction (Loyalist or Traitor) will control the System and will vote on where to invade next. Another option is for your local group or club to create a System in their preferred Sub-Sector and lodge the reports played within that group/club under the planets in that System, giving you a more localised game setting with your games have greater impact. These systems will become your Local System which is reserved for your groups use.
Whatever method is decided upon for the use of the Systems, each planet or other major location within the Systems will be contested locations with battles being fought over it. Each location on the System map will have a summary of its ownership in the mouse hover text box whilst clicking on the planet itself will take you to another screen listing all of the battles which have taken place so far with an Imperial date format and summaries of the forces involved and the results of the battle.
For more information on how the Battles and Campaigns impact the ownership of planets, please read this article.