Any = one or more than one of something, no matter how many.
Are there any apples?
He hasn't any books.Some = an unspecified number or quantity.
There are some apples in the bowl.
He has some books on his shelf.Something = an unspecified or unknown thing.
There is something in the cupboard and it's making a noise.
Will you bring me something from the shop?
Anything = A thing of any kind.
It is not anything to worry about. It is the cat.
I will bring you anything you want.
Someone = an unknown or unspecified person
There is someone at the door.
Someone wants to speak to you on the telephone.
Anyone = any person
Does anyone know who it is?
Is it anyone that I know?