It basically means surgically removing parts of your chronically enlarged/swollen turbinates so that your airways are free again. Along with that I've had a nasal spur removed (slightly blocked airways); Septumplastic (had a slightly deviated septum that also inhibited airflow a bit); and while at it the ENT also recommended and did FESS (Opening/Widening some paths to the sinuses).
It was a pretty life changing surgery that finally allowed me to properly sleep again, and do exercises/run while breathing through the nose. For some people, the turbinates may become enlarged again after a while, but for me it's been great for two years already.