Here's a VERY rough map, and I'll try to explain how it works below
BATTLEGROUND
To begin the battleground, you must be in a group of
4 people, all flagged for roles similar to dungeons (Tank, Healer, DPS, DPS). The siege towers will hit extremely hard, so you'll need a tank to taunt them while the DPS attempt to lay waste to them. The idea behind this is to promote team play, and make all roles viable. Occasionally, the siege towers will throw down AOE blasts, so if you're squishy you might want to step back!
PRIMARY OBJECTIVE
Your primary objective of the battleground is to destroy the enemy teams Guardian. That's it. To do so, you'll need to take down both of their Guardian Wards to disable its shield before you can attack it. This will be tricky as you'll need to also destroy the siege and enemy players.
The longer the game runs, the longer the resurrection cooldown is. So near the end of the match, it can take 40-50 seconds before a player can respawn.
STARTING POINT (Green Circle)
Should be pretty obvious what this is. This is where the players start and spawn when they die.
THE GUARDIANS (Red Circle)
Your objective to win the match is to destroy the enemy teams Guardian. They are shielded by the wards, so can't be killed while the wards are still alive. Guardians will attempt to defend themselves, but cannot move. Similar to Storm Atronachs summoned by Sorcerers.
GUARDIAN WARDS (Brown Circle)
These magical creatures have the primary function of keeping a shield on their Guardian. They're pretty busy doing this so won't attack you much, but if they're under too much pressure they will attack. Kill both of them to lower the Guardians shield.
SIEGE (White Circle)
Sieges are placed around the map, controlled by NPCs. The siege towers in your home base will NOT attack you (only enemies), but the ones in the middle of the map will attack anybody. You will need a tank to take the sieges damage, as a damage dealer will get melted by them pretty quickly. Occasionally they'll perform AOE attacks, but very rarely.
EPIC MONSTER (Red Triangle)
The "jungle" is the middle of the map, between the top and bottom lanes. You don't need to go in here, but if you do you'll find an epic monster on either side. Killing the enemy teams monster (the one closest to their base), will give your team a significant buff in spell/weapon damage and regeneration.
Once you start attacking the enemy teams monster, they will be alerted and can decide to try and stop you, or continue pushing towards your Guardian. The Guardian will differ between alliances. For example, the Covenant epic monster is a Lich, Pact monster is a giant Shalk, and Dominion's a... I dunno, an enraged Khajiit on Skooma or something.