Complex sentence: Most other Chinese immigrants started businesses in Bangkok's Chinatown, he set up his first shop in the Thonburi District on the outskirts of Bangkok across the Chao Phraya River from the city center.
Split into simpler sentences: Most other Chinese immigrants started businesses in Bangkok's Chinatown. He set up his first shop in the Thonburi District on the outskirts of Bangkok across the Chao Phraya River from the city center.