What do they mean by steength points??
The full term is Strength of Schedule Point.
It measures how difficult is your fixture or schedule.
To add on to what meng said, in VEX the strength of schedule points (usually shortened to “SPs”) are determined by the number of points scored by the losing alliance in a match (not, as I once thought, the points scored by the opposing alliance). The basic idea is that if the lower of the two scores in a match is higher, that must mean the match was harder.