Realizing that your body works in two motions helps you understand how you should train with free weights. Also understanding that the muscles that you exercised needs 24 hour rest as not to over work them is also important.     

Your muscles have two motions, pushing and pulling, and you train according to the motion your body moves. One day you exercise your pulling muscles. and the next day you exercise your pushing muscles. Do cardiovascular in the middle of the week. Then another day of exercising your pulling, and then one last day of exercising your pushing muscles. followed by 2 days rest.

The muscles use for pulling are you bicep, and back muscles, also a good day to do legs. Your pushing muscles are your shoulders, chest and triceps muscles.     

Once you figure out the exercises you want to do, find out the maximum you can lift for these exercises. There are two different types of "rep" styles you can do. 3 sets of 10 reps at 50% max will help you stay fit and tone while gaining strength. 6 sets of 6 at 70% max will help you bulk up and quickly gain strength. This is my choice. Doing 3 different exercises per muscle area..ie triceps, shoulders, back is all you need, if you do more you could overwork the area and then your weight training is useless.