Complex sentence: As soon as the tide was high enough, Matthew, accompanied by Howe and his troops, were ferried across the Harlem River and landed, under heavy fire from the American artillery, on the Manhattan shore.
Split into simpler sentences: As soon as the tide was high enough, Mathew and his troops, accompanied by Howe, were ferried across the Harlem River. They landed under heavy fire from the American artillery on the Manhattan shore.