These look completely different from Harvard references. The principles behind them are just the same, though.
If you use numeric references, you put a small numeral in the text, and then give all the information about it in a note at the bottom of the page (a footnote) or at the end of the essay (an endnote). Here's an example. It's the same as one of the examples from the material on Harvard references, a quote from a chapter (by Sarah Franklin) from a book (edited by two other people):
'the cultural construction of the natural facts of pregnancy' 1
1Sarah Franklin, 'Fetal Fascinations' in Feminisms ed. Sandra Kemp and Judith Squires (Oxford, Oxford UP 1997) p.489
That's it. It gives exactly the same information as a Harvard reference, but in a slightly different order
Numeric references are a lot easier to do if you are using Word. You can click on the References tab on the ribbon, then choose Insert Footnote from within the Footnotes group. Easy-peasy.