This is a huge castle siege map. I don't know any tricks here but I can help explain this map.
For the Attacker, the wood can be used to build 2 bridges up to the castle from the right and left hand side. It can also be used to make numerous blocking/protected areas between you and the castle. The red boxes can be used to build a cannon back near your respawn point. The cannon is loaded with cannon balls that respawn behind it. This cannon destroy the bridge on which the COP is planted. It will fall to the ground and be easier to capture. The cannon can also eventually break the Main doors to the castle to give easy access to the next spawn point. Beware, this cannon can also be captured by your enemy and used on you.