Working out?

i am just starting to work out and i got one of those big system things in my basement. the only problem is i dont really know what im doing. i know how to work the machine but i dont know what i am supposed to be doing or how much i should be lifting. i want to obviosly get bigger arms, pec, cut abs, and stronger legs, but i dont know what to do to get that. i also want to lose some fat on my chest and stomach area. the system has a "benchpress" thing and you can move the seat and the bar so you can do shoulders, it has a thing to do pullup like exercise and triceps pushdown, curls and seated rows, a thing for abs, this thing where you pull the weight from behind your head to the front for triceps, leg press, leg lifts or whatever they are called and leg curls and probably more. i also have a treadmill. can anyone tell me what i should be doing?