I'm a bit confused about the way Order Status Works.

I have four options
Pending (Default)
Procesing
Delivered
Update

I also use Authorize.net for immediate processing and downloads.

What is the logic behind this setup? What should the default order status be?
What to I set Authorize.net (set order status) or Paypal to use?
What option triggers the download to be available upon successful payment.

If I understand the logic behind all this, it will all become clear.

If this was addressed somewhere else, I apologize and ask for where that information would be

Thank you