How do I get sound on my Direct TV?

How do I get sound on my Direct TV? 

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  1. Slide the MODE switch to the AV1 , AV2 or TV position to. lock the volume.
  2. Press and hold the MUTE and SELECT keys until the green light under the selected switch flashes twice and release both keys.
  3. Using the number keys, enter 9-9-3 . (The green light flashes twice.)
  4. Press and release the SELECT key.