Newbie
 

I'm going to star lifting weights next week and a friend of mine made me a routine, is more like a circuit training, I'm going to work all the muscles 4/week
she gave me 4 sets of 20 reps each with little weight (5 lbs). I don't know if that is good, I don't really want to builk up, I just wanna lose some fat and get toned.

4 sets of 20 is really too much: you'll build endurance rather than muscle and strength. (That really becomes weight-lifting-as-cardio, rather than strength training.)

You'd be better off to do 3 sets of 10 reps, or even 3x8, and with heavier weights. 5lb is not a lot at all. What exercises did she recommend for you? (You will find that you can lift heavier weights with some exercises and need to go lighter on others. That requires experimentation.)

You won't bulk up--you might build a little muscle ('tone'), but you don't have the right hormones to get really bulky. Don't worry about that.

Biceps-Hammer curls, concentration curls
Triceps- overhead triceps extensions, triceps kickbacks
Shoulder-front raises, shoulder presses
Legs-Lunges,squats,calf raise, curls,cuadriceps
Abs-side bends and the normal abs

I'm a big believer in training the big muscle groups to do movements rather than individually working all the little muscles in isolation. You don't, for example, really need to work your biceps and triceps if you're doing presses and pushups. Presses, pushups, and rows work your bis and tris AND all the other muscles in your chest, shoulders and back. All those curls are kind of a waste of time (unless you are a bodybuilder, which you are not.)

I'd recommend doing something like this:

Upper body day: dumbbell presses, dumbbell rows, lat pulldowns, incline pushups. (I posted some links to videos of those exercises in another thread this morning).

Lower body day: squats, deadlifts (perhaps romanian), lunges/step ups, core work/planks.

Lifting weights 3 or 4 days a week, alternating upper and lower body days, doing 3x10 or 3x8, would be a really great place to start. (And you'd burn more calories because you'd be lifting heavy weights and really working all your big muscle groups at the gym).