Shader Editor not match selected material I selected the glass which is glass, but under the shading, all the nodes are the donuts. What did I do wrong that the nodes are not matching with the selection? 

Thanks a lot!
You selected an object. That does not necessarily select the material you intended to select on it. You need to do that in the Material tab in the Properties Editor:



In order to assign materials to different parts of an object you need to select desired faces in edit mode and click assign in the Material tab in the Properties Editor:



It is also quite important to name your materials appropriately. It might not be a problem for you now to have Material.001, Material.002 and Material.003, but once you work on anything more than a few objects with 3 or 4 materials, it will get very confusing if you don't name things. It's better to make a habit out of it.