weights!?

treesjg

Hi guys & girls

I attended a gym and use the weight machines. the gym instructor has given me a program for legs arms back and abs. But im not sure if I should train all these areas every session or alternate, so arms. One day legs the next etc.
I use the cardio machines too. I want to know I getting the most out of the workout.
The instructor have said to do all the routine every time for 3 months then they will do another program. But im really not sure this is right, would my body become used to this.?
Does anyone know what would be best. ?