I ve heard many different rulings on wearing rings. Although not from authentic sources but they make me wonder. Can you wear a ring on your index finger or is it haram? And can you wear it on your thumb or is it haram? And is it makrooh to wear it on your middle finger? (If haram and or makrooh, why so?)

Everything that relates to rings and the position in which you wear them on your fingers. Apart from the last finger and the second last are makrooh.