An Explanation of Galactic War

So i'm new to the Galactic War. Recently, my graphics card didn't work for PA but now it does, and last time I played (beta testing), it was just multiplayer. I have a few questions:

1. In order to win, do I have to conquer every planet?
2. Some planets have orange rings or red rings around them. Is that a faction or is there a certain level of difficulty on he planets?
3. Does increasing the size of the galaxy you fight in prolong the campaign/make it harder?

If you have the answers to any of these questions, please link them.

1: You have to defeat all the opposing 'faction leaders', that doesn't require you to defeat all worlds, however you have to defeat enough to reach them (once destroyed all their territory becomes neutral- i.e. not coloured).

2: The coloured rings around a planet denote which faction owns them. Planets without coloured rings are neutral- you should go to these first as you can recover technology to make your fight easier. Planets with coloured rings will have at least 1 enemy commander on, as you get closer to a faction leader planet the number of enemies increases.

3: Larger galaxy is usually a bit easier- although it takes longer. This is because you can scavenge more technology from neutral or low level (1 opponent) systems before taking on the faction leaders.

Edit: Sorry I haven't given you any links- there isn't a 'how to' on Galactic war right at the moment as Uber have only recently released it and they've already tweaked it a couple of times. I've already played through a couple so the above is based on my experience.

1. I believe you only need to defeat all the faction commanders
2. Different colours represent different factions
3. Galaxy size determines the length of the galactic war, but not difficulty. See above.
4. Why is there a pool and how does it help the discussion? Why is it even multiple choice?