In the Main Ops mission "Mine Base" involving the Miner's Residence, there is a bale of hay on the side of one the buildings. After cleaning up the guards, climb up the ladder to the building adjacent to the the one next to the hay bale, then roll to that building and when walking towards the edge, you would be prompted to press the action button. Sit back and enjoy the great Assassin's Creed homage and what I found to be an enjoyable 10GS. Hope this isn't complicated!