I noticed that a clarinet mouthpiece has three line marks sorrounding it. The first near the upper portion and the two on the lower portion. I guess that marks are guides for the ligature and has something to do with tuning the clarinet. What I dont know is where to initially place the ligature as an standard and the process of tuning.

And Is it the same when it comes to the alto and tenorsax mouthpiece?
Thanks to all