Simplify the following text for a Grade 6 native English-speaking person.
Original: Cyrus ( or his generals ) devised a plan to use the Euphrates as the mode of entry to the city , ordering large camps of troops at each point and instructed them to wait for the signal .
Simplified: Cyrus devised a plan to use the Euphrates as the mode of entry to the city . He ordered large camps of troops at each point and instructed them to wait for the signal .