you have a supply coming in. supply going out. (red blacks) a wire to your switch (red red) and a wire to a kitchen extractor fan i assume. quite a normal configuration. the project section on this sight explains all.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!