Read the sentence. From the start, he felt like a fish out of water at the new school. The other students had been there for at least a year. They knew where all the classrooms were. They knew the routines the teachers liked them to follow. He, however, was learning everything for the first time.

The author is most likely using the simile to suggest that

the boy was happy at his new school.
the boy was scared by his new school.
the boy felt excited about his new school.
the boy felt out of place at his new school.