I created a partition on my brand new, out-of-the-box 2014 Mac mini with the intention of installing 10.9 on it so I can boot into either 10.9 or 10.10. Obviously this new Mac mini already has 10.10 pre-installed. How do I install 10.9 on the partition? I have created a 10.9 boot disk but don't seem to be getting anywhere. What am I doing wrong? FYI my new partition is 150Gb.