@Paulbrom2001 Hi Paul, yes you can use an EAP110-Outdoor as a standalone access point. You will need to run an ethernet cable from your router to the supplied PoE injector, then another ethernet (shielded cat5e or above) from the PoE injector to the EAP install location. Just bear in mind the PoE injector will need to be located indoors and near a power outlet. 

I think the picture you are referring to is just to outline the possibility of wiring more than one EAP to your network. It is certainly not necessary.