Brew Step question

First time working with BeerSmith; simple question.  I'm making the Hubner Haus Habanero Lime mead and a fermentation step lists "Lime zest (primary 4.0 weeks)."  Does this mean I add the Lime zest at 4.0 weeks, or does it mean that the Lime zest will be in the fermentation for 4.0 weeks?  Thanks,  Keith

As I use BeerSmith, it would be adding the lime zest to the fermentor and keeping it there for 4 weeks.