You sound like a dumbass, but if you're in public education that can hardly be helped, so I'll try to explain symbolism to you.
The way your teachers explained symbolism to you is wrong. They did the whole "the curtains are blue to symbolize sadness" thing, which most down to earth people know is silly. They said that authorial intent is the driving force behind symbolism and that great works of fiction are great because the author mulled over every detail and assigned deliberate, conscious metaphor into everything that you need an official Media Literacy™, ivory tower decoder to understand. Basically, they taught you what propaganda was, called it symbolism, and said you had to interpret everything through a lens of approved propaganda formulas to get the most out of art and literature.
But symbolism is not a conscious metaphor sprinkled in by the author. Symbolism is metaphor that is embedded into the elements of the work whether the author intents it or not. There are symbols that vary across cultural context, and there are symbols that are universal, but the meaning is embedded into the objects themselves.
Ex: Closing a door. You could say that closing a door is symbolic of rejecting what is outside of the door. You could also say it's symbolic of protecting what's inside with you. Both of these are correct. A door is symbolic of separation, because that's literally what it is. A desert is symbolic of a great, prolonged hardship because that's literally what it is. A dragon is symbolic of an insurmountable challenge, because that's literally what it is. The meaning is embedded into the material whether the author wants it there or not. You don't escape it.