Complex sentence: Grandpa tells him that he wrote to the circus asking for a method of how to catch the monkeys; the animal trainer responds to him telling them to call Jimbo by his name and try to make friends with him.
Split into simpler sentences: Grandpa tells him that he wrote to the circus asking for a method of how to catch the monkeys. The animal trainer at the circus responds, telling them to call Jimbo by his name and try to make friends with him.