The Covenant-Human war is long over, but complications still arise. A band of Covenant-loyal Sanghelli have set foot on Installation 07 and are preparing to fire the Halo array with its Index. The marines is not about to let that happen. The UNSC has supplied a flight of falcons and some borrowed elite weaponry. But the Covenant Loyalists are heavily fortified.

Overview.
The Attackers' main base is in the foreground. The Attackers can spawn there during all 3 phases if they wish to bring in some falcons.
http://img813.imageshack.us/i/takeover1.jpg/

Phase 1.
The capture of this communications array will prevent the emergency fire signal from being sent out to the remaining installations. This screenshot was taken in forge so you may see the small blue hill marker infront of the orange coloured strut. 20 seconds in the area will prevent the signal from being sent.
http://img826.imageshack.us/i/takeover2.jpg/

Phase 2.
This bridge is used to send Sanghelli supplies between bases. Cross the bridge and blow the supply crates so the heavy vehicles can come in for phase 3. The catwalk on the bridge is accessable from the island where the UNSC spawns for phase 2. A sniper rifle and a sprint ability are up there for the marines.
http://img826.imageshack.us/i/takeover4.jpg/

Phase 3.
The Sanghelli can still fire the Halo array from this station. Retrieve the Index and bring it back to the UNSC base. The UNSC get a foward falcon, a scopian, a warthog, and 2 rocket hogs. The elites get a compliment of heavy weapons and a large bunker. The intel core spawns a couple yards behind the deployable cover on the grass, right in the elite's firing zone.
http://img826.imageshack.us/i/takeover3.jpg/

Play ONLY with Invasion Takeover gametype (listed in the custom game slot at the top). 2 rounds per game.