Ubercart file download — how to make things easier

On a Drupal 7 site that I developed, there’s also a ‘web shop’ part, where visitors can buy physical and – currently being developed/implemented – file downloads). This is done using Ubercart 7.3.

This shop uses just one type of payment – bank transfer.

I have managed to set it all up, entered the relevant products with their attributes (files) and everything works fine, apart from the last step – downloading files. It’s a bit too complicated and I am sure it can be automated.

So if a user buys a digital download, the owner waits for the payment, and after it is transfered, the admin changes the status of the order to complete.

After that the buyer is, if option is checked, notified of the download, but admin must then manually assign the file to be downloaded by the user… Or am I doing something wrong?

Is there a way to simplify, or better said, automate this process, i.e. when the status of the order is changed to complete, the download should automatically be made available to the buyer.

Also, I would like to change the template of e-mail status change notification, but don’t know where it’s located. Is it somewhere within rules?

Please help me and thanks.

Drupal version: 

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