character is one component, camera is another. First you must know what exactly u are gonna achieve. if ‘use control rotation’ check box is checked, your camera automatically read from mouse input (if mouse input is already set in project settings). By default it is checked. but for some rare situation you may want to uncheck it and manually set camera movement based on mouse X/Y input nodes. you don’t need to go through c++ for doing what you need. The thing is first you must have a solid understanding of rotations and how they are implemented inside unreal engine. I have answered a similar question a while ago. check it it may be helpful.