Verbs show "action" or a "state of being."
Action words are easier to identify - run, jump, walk, draw, eat, drink, etc.
State of Being verbs include all forms of the verb "to be" (all tenses such as the present, past, and future) such as I AM a teacher. I WAS a teacher. I WILL BE a teacher.
That's the definition of verbs.
Now, verbs also have what I call "jobs."
They can stand alone: I JUMPED over the ball.
State of Being verbs can help: I WAS JUMPING happy yesterday.
State of Being verbs can link: I WAS happy yesterday. (The verb "was" links "I" with "happy."
Other STATE OF BEING verbs can be used as linking verbs such as - She SEEMS happy.
Rather than memorizing certain words as being verbs or not, it's important to look at the "job" that the word is performing in the sentence.
I hope this helps. Please feel free to register for a tutoring session. 😊