Where should we start learning literary writing, from writing prose, novels or poems, or from one person to another? Everyone laughed at my poor level.

The classification of prose novels and poems you mentioned earlier is correct, but the latter is neither fish nor fowl. You can use any kind of literary material to write about a person and a thing, including prose, poetry, novels and plays. If you want to learn writing, I suggest you start with prose. Prose doesn't pay much attention to the format and rules of writing, but only remembers that "keeping a diary is good, but I think it's just an exercise."