A link is a way of getting to somewhere (or something) else. For example, i have a mouth and i might also have some food. I would use a link between these two items which usually takes the form of my hands, a fork and maybe even a spoon. Another type of link can be a chain, be it metal or another strong material. Humans sometimes use these to secure items e.g. bicycles, motorcycles, faces etc.
Don't get these two confused as it can lead to injury. I had to find this out the hard way. I tried to use a metal chain to link my bottom to the toilet seat and woke up in Hospital. The nurse said i was traumatised and in need of thorough cleaning. The most embarrassing thing was that I hadn't waxed my buttocks for a month.
You can see how understanding links and when they are appropriate is of high importance.