My notes folder has no tag browser. Why?

Are you using iCloud Notes? Did you follow the steps shown in the Related Article. One step is to ensure that you do a space after you have typed the Tag. Watch what you are doing, type the #, then no space type the tag. After typing it such as #Tag, after typing the g, hit the spacebar, then watch to see that the tag changes color. See if that works.

They are referring to this, I've circled in red.

If they do not appear as Tags, check the note, make sure the tag appears a different color, then it should appear. Also check the Settings for Notes and see if you have Auto Convert to Tag, to make sure that it changes what you add to a tag.