My brother had been gifted it a long time ago, and I recently picked it up to see if I could play something cool.
There's a problem, however: most instructions online are type-specific, but I have no idea what type this one could be. It has absolutely no engraved information and is quite different — having 16 holes and a single reed plate, with 16 singular reeds that alternate up and down.
If there's no definite answer, what are some tips to overcome this type barrier and learn to play the harmonica?
Oh, I'm sorry for the misunderstanding. It is like that because I had taken it apart to understand and show its interior. Nonetheless, though, they have nothing stamped on them.
About the tuning, don't chromatic harmonicas have a lever and tremelo and octave ones have a double reed plate?
My bad I missed that it’s only a single reed plate. In that case it’s possible that it was an educational use harmonica. Check out this article I found when looking for 16 hole single reed plate harmonicas (towards the Single Harmonica section or maybe a half viennese) https://patmissin.com/ffaq/q36.html