In this video, you will learn about broken springs. He does not recommend replacing all types of garage door spring sets. He has a more generic set of springs for his garage door.
He ordered replacement links online and it included a printed set of instructions. The set of instructions are really good and easy to follow. You will want to start at the top of the garage door. How you determine what is still working is hard. If there is any tension on either spring, it should not be allowed to spin freely. Cables will run down the doors. The strings that are inside will either be both broken or one broken. If one is still working, you will need to follow specific instructions to be able to remove the spring. There will be a lot of tension in the springs. If there is no tension on the springs, they will be easier to remove. There are two bolts on the brackets in the center. You can remove a pin that is along the spring to give it enough clearance to remove the spring. If you are interested in learning more, keep reading this for more information.