Can someone show me how to make a Following Script?

I made a snake model that has 3 parts and a Humanoid part in it also. But I tried making a following script and it didn't work out so well. So I was wondering is someone could help me?

If you made a following script, show us it and the output of what happened when you tried to ran it. You have to debug..

This isn't the place to ask for scripts to be created for you, this is for debugging scripts