If you use anything from another source you need to cite it whether its a diagram, idea or general info, when you click insert citation it creates an in text citation but all the info that is being entered is for the bibliography at the end. In text citations are only author and year but there can be a lot of stuff in the bibliography entry depending on the source type. I know that websites you have to also enter the last time it was edited and the date you accessed it, journals need volume and issue as well with page entry. That site I gave gives whatever you need to enter.