you are essentially blocking your lights by placing a BSP box brush around your whole scene, try using boxes as walls, floors, ceilings, etc to create your room. The box you have is single sided and is not visible from its back faces, its also a BSP and not a static mesh, so that might be something that you will want to change. There should be some walls with openings for doors and windows in the starter content that you could use instead, otherwise you will have to make them yourself in a DCC like Maya, or Blender.
To place a point light you will have to select it in the details panel under the lights tab, or you can hold down the L key and left click in the view port to quickly add a point light.