All you need to know is on this site.
Click onto Borovets and scroll down the left side till you get to the Borosport advert. CLick on that and it's all there.
There are three chair lifts - one hi-speed four man chair taking you up to the Stinkyavo area (the 6km green and some reds run from there), there's the Ystrabets hi-speed 4 man which takes you up to the red runs there and there is the original chair lift opposite the Rila which takes you up the reds there.