Dear community

I have just read the "tutorial" on how to add digital downloads (via. link) - I purchased one of my own products for testing which works great, I just have 3 questions:

1. I noticed that the order status was "Processing", I was waiting and waiting but without getting any results, my questions is, if it's possible to "delivery"/accept the payment automaticity?

2. I accepted the payment manually and set the status to "Delivered" - I then went to "My Account" to "download" the file but when I click on the download bottom it redirects me to a white error 500 page (pub/.eyrgvpowtfqxsmfisv/Nepty.rar)

I made sure that my PUB folder is set to 777, and my DOWNLOAD folder is 755.

3. Do made a discount for "Gift Certificate" (just for testing), I then entered my coupon code and noticed that it was valid for all products.
How do I apply a coupon code for 1 specific item?

Cheers,
Mike