Why did Dumbledore go to Tom Riddle to talk to him about coming to Hogwarts?

Dumbledore wanted to make Tom Riddle a better person, and he knew that Tom could do magic.  He could tell that Tom Riddle had evil thoughts, but Dumbledore gave Tom Riddle another chance.

How did the mirror of Erised become property of Hogwarts?

It might have been the property of one of the four founders of Hogwarts, but no one really knows.  The mirror of Erised shows you what you want, and the one who looks into this mirror will only see himself exactly as he is.

How many wands did Voldemort use?

Tom Riddle (Voldemort) only had one wand of his own.  He stole four wands during his life to do evil things.  The picture above shows one of the wands that Voldemort used to try to kill Harry Potter.

Why did Hagrid bring Aragog (the spider) into the dark forest to live?

Tom Riddle framed Hagrid and the spider for killing people at Hogwarts.  Really it was the basilisk, and Tom Riddle was controlling it.  Hagrid helped Aragog to escape.

How did Tom Riddle find the horcrux ring?

Tom Riddle had the ring.  It belonged to his mother.  He put part of his soul in it.  He made a lot of horcruxes.

Why does Peter Pettigrew work for Voldemort?

Peter Pettigrew found Voldemort in a forest and decided that Voldemort was protection for him.

Who was Peter Pettigrew?

Peter Pettigrew used to be James Potter's friend, but he betrayed James and Lily Potter to Voldemort.