How do I get Mendeley to cite with et al when more than 2 authors?

Sorry, could not find this in the tutorials. I am required to cite using Harvard Anglia Ruskin - currently I am having problems getting the citation to automatically list author et al.,year. Is there a way of altering how Mendeley cites the names in the reference and the bibliography please, so I can use this format everytime when more than 2 authors. Thanks