He wasn't afraid that the training would be tough. He was a farmer and could bear hardships. However, he didn't expect to be using his brain at all. He also felt that he didn't have the brain capacity to hold anything.
He didn't know that he had to study and read in the military camp. If he had known, he probably wouldn't have followed Sanfu to this military camp.
It was a good thing that he had gotten used to it over time.
He couldn't sleep for the first few days, especially when he and Sanfu were assigned to different tents. They didn't train together. He trained with the new recruits, while Sanfu was personally trained by someone else.