I am finally getting around to looking at the whole branding piece for SharePoint 2013 and I was following this MSDN Article this morning and noticed that I couldn’t see any link to the Design Manager in Site Settings as the article appeared to allude to.  I did notice however that the article mentioned publishing site, so I simply enabled the Publishing Feature at the Site Collection level and the link appeared as in the article.

Hope this helps.

Cheers

Dave Mc