Use of the word "De"?

Use of the word "De"?
 

So I know that De makes things belong together. So I can say "Tú y yo somos de Nuevo York." But the equation I was given Noun + De+ Owner
And then saw the sentence "Es el Dario de Maru" So under this logic am I correct in thinking that........
1. Things belong to the person
2. Person belongs to the land


Also if "¿De Dónde es Jack?" means "Where is jack from" Can you then say "¿De quien es la computadora? to say "Who's computer is this?"

You've discovered that 'de' means 'from', when used as a preposition and followed by a noun (prepositional object).
When used between nouns, it is also the way to express possession, belonging or affiliation (association). For possession, it's the equivalent of the English genitive. For example, el padre de María = Mary's father. For this meaning, 'de' translates as 'of'. (the father of Mary = Mary's father)
For the meaning of belonging or association, 'de' translates as 'from'.

Just as '¿De dónde?' means 'From where?', '¿De quién?' can mean 'From whom?'. However, it can also mean 'whose' (not who's). With that meaning, we are talking about 'Of whom?' (expressing possession instead of 'of' (the preposition)).