Complex sentence: For the next several years Busan would be a supply depot and the Japanese would continuesly supply troops and food across the sea to Busan until Admiral Yi Sun-sin attacked Busan later with his navy.
Split into simpler sentences: For the next several years Busan would be a supply depot for the Japanese. The Japanese continued to supply troops and food across the sea to Busan until Korean Admiral Yi Sun-sin attacked Busan with his navy.