Any map, you must reach the fifth set with another person on Heroic or harder.
Here's how you break it down.
Five waves in a round.
Three rounds in a set. (Plus a bonus round and the end of round three)
You must get to set five.
1. ODST
2. MA5C Assault rifle (Reach version)
3. M6C SOCOM
4. Halo 3 style ODST armour. Has been reinforced with additional metal plates in the field. Has "Remember Reach" carved into the chestplate.
5. Drop shield
6. Fragmentation
7. "Paladin"
Well certain parts of the forum (Offbeat and introductions as far as I know) don't give points towards the post count.
You have to post in other forums like the halo 4 ones.
But don't spam posts or necro old threads. The mods frown on that sort of carry on.