After spawning, you need to turn right and move ahead until you see two blocks. Then, turn right and dig down as the red circle mark of the following picture.
How to Play 2 Mob Spawners Under Spawn Seed?
Dig down until you find the ceiling of the dungeon. Fall down and discover the dungeon. Remember to wear appropriate gears for more safety.
Pass the first mob spawner and you no longer find the tunnel system. Turn left and see the second spawner.
Two chests include 1 wheat, 1 string, 3 iron ingots, 6 bread, 6 gun powders.