Casper began to search on Yanke's consciousness for his memories. At first, just shallow information appeared. However, as he focused his mind on the task, new things appeared.
Looking into Yanke's memories was just like switching from the screen of a television to another one. Just with a turn on his head, or a glance, it was possible to look at what was going on on each screen.
By doing this exercise, accessing those memories got easier. He didn't think that it would be that simple and quick to take a grasp on it.
Anyway, since Yanke was now part of Casper's consciousness in the most intimate way possible, it was just natural for him at that point that he would be able to control this. It was like having another extra limb; you tensioned all your muscles until you found the right one to move that new limb. It was strange, but not difficult.