"Use the Rope Dart to hang 2 guards" is an optional mission objective in Sequence 11 / Memory 03: ... Everything Is Permitted
Walkthrough[edit]
Using the Rope Dart to hang 2 Guards is best done after you pass the third or fourth marker on your way to the shore. Head onto the nearby tree and look down. Select the Rope Dart and target someone. As Edward pulls them toward him, move away from them. Edward will drop down to the ground and plant the rope to hang them. There are a lot of enemies in this area and it is easy to climb back up into the trees for a second target. Just repeat this once more, using the same tree to quickly complete this objective.
