Uh, what?
Mundane Fantastic, as far as I can tell, is a matter of tone and presentation, not any particular plot elements. If you want help to write a story, you're going to need more than just a vague idea about your story's approach to the supernatural - a main character with a goal would be nice.
There is no real goal for any of the characters; it's a high school slice of life, but with rapid fire jokes, characters getting into fights, and so on. Like a parody of a High School drama with comedy as the focus.
Oh sure, if it's just an endless series of muck-about vignettes, then no, your characters don't need goals.
But if you actually want to have a plot - that is, an actual narrative, with a beginning, middle and end - then your characters need goals.
I am a pretty big fan of the Mundane Fantastic trope, and I think it works the best in a arc-based plot structure. I would like some tips on how to structure a plot like this well.