For this exercise you will need a long bar normally the ones you use when you do chest exercises, this bar should be on a rack. Put the bar behind your head and on the back of your shoulders and take a step or 2 back. With the weight on the back of your shoulders squat down, lean slightly forward and keep your back straight and come back up to standing position. Do this nice and slowly and make sure you do NOT add weight too heavy as it can result in serious injury.
For this exercise there should be a seat that is tilted and an angle and in almost touching the ground and there should be a metal plate where you put your feet on directly above the seat. Sit on the seat rest your feet on the plate, let it your knees come to your belly and then push the plate out with your legs. Repeat and make sure you do it nice and slow.
This is another great way to work your legs; you sit on the bench place your feet underneath the pads you have a handle to hold on to your side for support. Start lifting the weight nice and slow to work those quadriceps, make sure your comfortable and start on a weight that you can manage. This workout will surly build some mass on those legs.
4] Seated calf raises
This is a machine that works your calves. There is a seat that you sit on and some pads, which you place your knees under, and a toe rest (foot rest but half the size only for the top half of your foot). You lift the weight by tiptoeing while seated. Do this nice and slow to get full benefit. You can also do this standing where the weight will rest on your shoulder and you lift the weight by tiptoeing.