Russian version of the article is available at the link.
To create a pre-order (future order) via operator app first of all make sure that this feature is enabled. Proceed to My Hub "Service Types" tab and check the status of pre-orders feature (Instant or Delayed broadcast should be enabled)
Now while creating an order via operator app simply click on the date&time's field and choose the details of pre-order.
Pre-order can be done from 15 minutes in advance. You can change the minimum period for pre-order in the general settings of a service type in the range from 15 minutes to 96 hours.
"Clock" is a special sign for pre-orders in operator app.