Complex sentence: For four years he worked at the Hotel Elliott, developing his pictures in the laundry, before relocating to the growing city of Okanogan in 1907 where he built a two-room store on First Avenue which served as studio and darkroom.
Split into simpler sentences: For four years he worked at the Hotel Elliott, developing his pictures in the laundry, before relocating to the growing city of Okanogan in 1907. In Okanogan, he built a two-room store on First Avenue which served as a studio and darkroom.