Imported Mesh - No Option to Set Collision Complexity?

So I created a mesh in Maya and exported as an FBX file. Upon importing it into Unreal, my character walks on top of the entire object which means the collision is wrong. Watched youtube videos of people being able to set the complexity of the mesh collision in the object window. However that is not even an option for me, its not there whatsoever. So how do I change the collision of my imported object???