Although you have mentioned having no problem placing the light, here is a rundown of all the steps that worked for me, in case anyone else may benefit (these tips were shared by helpful fellows on this here forum

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- Create the light itself as a separate project, a box of about 1 foot square works well. Under Part Properties, create a new Material colour, you can name it light_red, with values in all colour boxes (Diffuse, Ambient, Specular & Emissive) at 255, 0, 0, 255 respectively.