Hi,
I think you are getting very confused.
if you add "5" to an array, this is just an int, you need to ave in the array the GameObjects for each platforms.
then as you get a random index in that array, arrayList Get will return you the platform for that index.
try to remove all your disabled actions, don't create the array at runtime, and drag your platforms in the array during runtime, and see how it behaves to take a hard coded index, maybe 3, then work your way into making it then random.
Bye,
Jean