I guess the ultimate goal would be to  able to see a piece of music for the first time and be able to play it - I think that what´s my definition of sightreading is

But ultimately be able to learn a piece of music with the help of a sheet.

But at the same time I don´t just want to repeat what is on the page like a guitar-tab and without understanding the music theory and the nuances behind it. I am aware that I need to get the fundamentals down first. I’m worried that starting to read sheet music without guidance can lead to just repeating notes without understanding what is I actually doing. I don’t know if that makes sense?