Simplify the following text for a Grade 7 native English-speaking person.
Original: Celebrated annually on 26 January , the date commemorates the arrival of the First Fleet at Sydney Cove in 1788 and the proclamation at that time of British sovereignty over the eastern seaboard of New Holland .
Simplified: On 26 January 1788 British people entered the country at Sydney Cove and made it their new homeland .