Complex sentence: As a youth, he evinced a taste for drawing, and was advised by Sir Joshua Reynolds to enter the Royal Academy as a student, but in 1787 he was placed in Hookham's publishing house.
Split into simpler sentences: As a youth, he evinced a taste for drawing, and was advised by Sir Joshua Reynolds to enter the Royal Academy as a student. His stay at the Academy was short and in 1787 he was placed in Hookham's publishing house.