How to do the Seated Row
Description:
From the seated position pull the handles towards your chest and slowly release back to the starting position.
Seated rows using cable station 
or machine
How to do it:
1. Whether at a seated row machine or cable station, sit facing the machine.
2. Your feet will be in foot locator's. There should be a slight bend to the knee's. Adjust the seat height (if there is one) so that the handle grips are located even with the center of your chest.
3. Place a wide grip bar on the cable if its a cable station, and grip the bar so that your arms are wider than your shoulders. On a machine grip the widest handles.
4. On a machine the chest pad located away from the machine enough so that when you hold the handles your chest is against the pad and the weights have been lifted off the rack a little. On a cable machine sit leaning slightly forward with a straight back and the weights off the rack so that with straight arms there is tension on the cable.
5. On a machine pull the handles towards you as far as you can and slowly release the weight back to the starting position. On a cable machine pull the bar towards you until the bar touches your chest and slowly release back to the starting position
Do’s and Don’ts on Cable:
1. Don’t bounce the weight off your chest. It is cheating and dangerous to do so.
2. Don’t do the "rolling stop" at your chest. Hesitate then release.
3. Don’t jerk the weights off the starting position. Start with a smooth pull.
4. Don't sway your upper body back and forth. You are starting in a slight lean forward, as the bar comes to your chest it should be an equal slight lean back.
5. Do keep your elbows up and wide. Have your forearms parallel to the floor.
6. Do squeeze your shoulder blades together as the bar gets to your chest.
7. Don't take the tension off the cable until the set is complete.
Do’s and Don’ts on a Machine:
1. Don't let your chest come off the chest pad.
2. Don't move your feet.
3. Do keep your elbows up and wide. Have your forearms parallel to the floor.
4. Do squeeze your shoulder blades together as the bar gets to your chest.
5. Don't take the tension off the machine until the set is complete.
Variations:
Bent over barbell or dumbbell rows. I do not recommend these to relative beginners. They place a ton of pressure on your low back and maintaining good posture with these is very tough.
Muscle building importance:
Used to build thickness in the back, biceps, rear deltoids, traps, lats and rhomboids. The do all compound move for your back. A well developed back is needed to balance all chest and shoulder work. Seated rows in some variety or fashion will be a part of your muscle building back routine forever.