How to get the keys for Microsoft Office 2013 from Microsoft Open Licence Order confirmation

I was able to download the iso file of the Microsoft Office (OfficeStd 2013 SNGL OLP NL Acdmc) and install it to 7 computer according to the license agreement. I don't know where to find the keys to validate these installation as required by Microsoft Office. I need  help please. I bought the License from a Computer Equipment  Business and this License confirmation is all I have so the reference http://office.microsoft.com/en-us/buy/using-the-product-key-card-FX101853163.aspx is useless for me . I already tried.