I'm trying to do some habitat suitability modelling on QGIS. I've downloaded several vector maps from Ordinance Survey (OS). So far I've found a Cartographic stylesheet for "OS VectorMap Local". This seems to work on Qgis. When I downloaded these there were GML style sheets which could be uploaded by going into properties --> style --> load style.(http://hub.qgis.org/projects/quantum-gis/wiki/OS_Styles)
However I also need other elements from a topographic OS MasterMap Layer and I can't find any styles that work for it.
I've found Styled Layer Descriptors (https://www.ordnancesurvey.co.uk/business-and-government/help-and-support/products/styled-layer-descriptors.html). However when I downloaded it it was just text files and ".sld" files. Which I have no idea to use as a style in Qgis.
Any suggestions?
I don't think it should make a difference but I'm using a mac.
Using the comment below I added in a the sld style to the area and go this:

What I was expecting was something like this: (from the VectorMap style)


