traktor not giving me the correct bpm

[djxsquizet]

Ok I am getting ready for a show and it will be my first time playing out with traktor. I have the gist of it, I just cant get my head around gridding(i already watched the vid on it, just need some practice getting used to it). Also I am playing dubstep, so one track it will say its 143 bpm and another track it will say it is 70 bpm, how do i fix the bpm on it, cause i know the song is really not 70 bpm's

[Jester]

You can double or half the bpm under the gridding section mate.

[djxsquizet]

ok thanks