How can I do this?

I cannot figure out how to mute the default players sound so you can hear other sounds. Is there a way you can mute the players sound?

All the sounds are in the character's head. Now lets use the PlayerAdded and CharacterAdded Service. You may look these up on the wiki.

game.Players.PlayerAdded:connect(function(player) --When a player joins
	player.CharacterAdded:connect(function(char) --Get the character
		local head = char.Head:GetChildren() --Get everything in the head, like sounds and faces.
		for _,sound in pairs(head) do --Get everything in the head
			if sound.ClassName == "Sound" then --If it's a sound, not the face or anything.
				sound:Destroy() --Get rid of sound.
			end --END
		end
	end)
end)

Hope this helps!