Trebuchets and Ballistae:
To create a trebuchet,t simply walk up to a siege camp (big orange tents that you can build on those piles of rocks aka siege camps that you hopefully marked earlier) and click it. You then select which plans in your inventory you want to use and viola, a siege weapon of your very own! These little puppies will start firing by themselves, but while they do it is you and your raid's responsibility to let it do as much damage as possible before the defenders take it out. And trust me the defenders will come at these things like wild dogs.
*TIP* using the advanced trebuchets is highly recommended as they have a great amount of hit points, meaning it will get off at least one shot before it is taken out ( it costs a lot more though so is recommended when attacking the main keep directly).
For defenders, there will be special NPCs that spawn on certain towers during the siege. Talking to these guys will create a ballista on the tower and give you an item (so make sure you have inventory space!) using the item will create an AoE circle that you can put on the ground wherever you think the enemy might be. The ballista will then fire continuously at that spot until either you die, the tower is destroyed, or you give it another location to shoot. The ballista will not do any damage to the attackers but it will be a constant knock back AoE that ignores most anti-cc.
*TIP* Ballistae can fire behind the tower they are mounted on! Some attackers will overlook a tower they have already gotten past allowing you to set a knock back zone in very annoying places!
Getting to the battleground:
Use the Massive PvP tab to find which of the three border kingdoms you will be attacking. To get to the Aquillonian end go to the border kingdoms recruiter at the garrison just a bit up the street from the temple of Mitra. For the Border of Kush talk to the recruiter near the armory in Khemi. For the Cimmerian end talk to the border kingdoms guide right across from the wagoner.
You can also go to the border kingdoms straight from any of the resource zones. Purple lotus swamp=Kush, Poitain=Aquillonian end, Lacheish Plains= Cimmerian end.
Once you arrive, simply check the local map for which BK you are heading toward.
If you own a BK then all you have to do is talk to a special NPC in your guild city who can port you there instantly for a small fee.
The Basics of Siege:
When the time for siege comes, there will be a guild wide message along with a counter that appears in the top left of your screen (default). This counter will show the defending guild's name along with a certain number along the attacking guild's name next to a zero as well as the time left in the siege. The numbers next to the guild names are the amount of points the defending guild has from their buildings (The higher the tier of the city/ more buildings the more points they will have). Every time a building or wall takes damage or is destroyed, points are lost from the defending guild and given to the attackers. To achieve complete victory, causing ownership of the BK to go over to the attackers, you will not only need to destroy the keep itself but have more points than the defenders. For attacking guilds that already own a BK; only the keep itself needs to be destroyed for a victory to show up on your record, though the defenders will still own the land as a guild cannot own two BKs. This will reset a T3/T2 keep back to T1, however. Destroying buildings for points is not the only advantage you get from destruction. The defending guild will lose any bonus they gained from the building as well.
Siege can be one of the most intense PvP experiences in any game but having 48 v. 48 max in a zone can be very taxing on even the beefiest of computers, so turning down settings is a must if you do not want to experience lag or a disconnect because of high latency. There is a nifty little siege/raid setting that will work for most computers but most high end systems will only need to turn view distance down and particle effects off.
Sieging has some of the highest stakes PvP out there, so you can imagine that there are countless strategies out there used to achieve victory. From the more underhanded tactics such as planting spies or using a mammoth mount to block the targeting of siege weapons to the more creative ones such as defenders paying off a mercenary guild or creating a dummy guild just to grab their keep's attacking spot and effectively get a free siege win. Each guild has their own play style and strategy that they bring to raiding and sieging alike. Just be sure to end the battle on a good note, even if your keep is razed to the ground and the corpses of your friends lie strewn over the battlefield just remember that you can come back the next week and take it right back!