Prefabs are not being dragged into the scene ,Prefabs are not being dragged into into scene

Hi! I am really new to unity and I am trying to make a project using the roller prefab but unlike the videos I have seen my prefabs are not being dragged and dropped into the scene. Can someone please help me with this?,Hi! I am really new to unity and I am trying to make a project using the roller prefab but unlike the videos I have seen my prefabs are not being dragged and dropped into the scene. Can someone please help me with this? I am using unity 5.6.7f1 for a 64 bits windows

@TheCreator117 Can you maybe show me what happens when you drag the object?