Hi, 4.4.4 stock rooted to 5.0 lollipop question topic

Hi,

I am currently running a stock but rooted nexus 5 on kitkat 4.4.4. I want to do a clean install to stock but rooted lollipop 5.0.1. What is the best way to do this? Any tutorials? I am running a mac - As I mentioned I want to do a clean install so I am ok with losing everything.

Thank you