Next, if you don’t find an obstruction, check the springs. If your door has torsion springs, which are horizontal at the top of the door, you can tell they are broken by checking for a gap between the two springs. If your door has extension springs, you can check by looking to see if they are hanging on the side of the door. If you have a broken spring, you’ll need to call a pro to replace it as this is a dangerous task.
Because garage doors are large, heavy, and mildly complicated, most people who buy them take advantage of these services. But, if you’re pretty adept at DIY tasks, you can save some money and enjoy the satisfaction of doing the job of installing a sectional garage door yourself. (Sectional garage doors travel up and down on rollers that ride along tracks at each side of the garage doorway.) https://www.youtube.com/watch?v=Z_eZc-kh40c&feature=share
4.4 Take the spring on the left and place it at the left end of the door as pictured here. Notice that the end of the wire points to the right toward the center of the door. This is a right wind torsion spring. It will go above the garage door on the left side of the spring anchor bracket. The winding cone at the other end of this spring is usually painted red.