I am not a teacher, but I am a native speaker.
It sounds like you actually have a pretty good grasp on this. I added a link to the bottom of this post that gives a list of the different parts of a sentence. Maybe the way someone explains parts of the sentence make it sound like every part is describing a thing, but really, only nouns describe an actual thing.
Basic Parts of Speech - English Sentence Structures and Parts of Speech
- For Teachers