yes exactly we use them to convey possessions just like

benim adim = my name is (nim is equivalent to my) my is a possessive pronoun

so in the case of (şu, bu, o) we can use the prefix (nun)to relate to possessıves

onun kitabi tut= hold his/ her book ( here onun is used instead of his/her which are possessive pronouns )

am i making any sense to you?

bunun rengi guzel= it´s colour is beautiful

What you just said there in a sentence was what i tried to explain in a with a whole paragraph. haha

Ahh thank you

Haha, might have been a paragraph but you still got it right!

well actually i did send a paragraph of explanation but my pc got stuck while it was sending so it only sent the first 2 lines twice and then the third time it sent i all so if you check the previous replies youll see what i wrote in explanation

 Yea you right, it basically means belonging to - şunun tasması siyah - this collar owns the black colour

if you wanted to say something like ´the door of the car is red´ - arabanın kapıyı kırmızı - basically it´s saying the car owns a door that is red

red = possessive suffix ie. the car owns

blue = fusion consonant between vowels

purple = something like ´the´ ie. the door