Difference between Unattended and Non production robot?

Hello, I have gone through https://robot.uipath.com/docs/about-licensing and NonProduction/Unattended pages and tried to understand about Unattended and Non production robot.

  1. Can any one please tell me how unattended and non-production robots are different ?
  2. If I have bot machine with unattended bot licence, can I use it on production environment ?
  3. How do we get/set runtime ? How does run-time work with the bot which is having unattended license?

Nonproduction robots will be assigned to development environment and unattend robot will be assigned for ITG or Production environment.
from Orchestator, can schedule the job depending on the business requirment.
Means bot has to run how frequently minutes, hrs, daily etc