Simplify the following text for a Grade 6 native English-speaking person.
Original: The Cayman Islands Civil Service College , a unit of Cayman Islands government organised under the Portfolio of the Civil Service , is also located in Grand Cayman .
Simplified: The Cayman Islands are a territory of the United Kingdom in the Caribbean Sea . The three islands are Grand Cayman , Little Cayman , and Cayman Brac .