Are you asking how the coin mix can make it hard to determine ownership or how the transactions are formed?

If it is how the mix works you could think of it as mixing water.

Imagine multiple people each hold a glass of water and you can see who holds each glass. If you watched person A pour the water from his glass into glass B you could easily see the history of the water. You would know the water in glass B belonged to person A.

Now imagine all of these people pour their water into a big jug and then the jug pours the water out into multiple glasses. You would know who put their water in but at the end you would have no way of knowing which glass of water belongs to which person