When a task is scheduled you can click on the task name or any of its details and it it will pop up a progression tab.

From here you can progress the task by dragging the slider, you can update the Start date and the Due Date. And if you have completion checklists these need to be ticked off prior to this task being able to be completed.
If instead you click on the Icon button, you will navigate back to the schedule screen.

From Here you can click on the Action button at the bottom right.

The Following Actions can be performed.
Split Tasks:
A split task is a duplicate of the original task and is used by the Supervisor when there is a need for more than one call out or notice of the task to the supplier. The two options given are to enable the system to label the task so that the purpose of the call out is more obvious.
Multiple Callup – this option labels the task as // Multiple Callup and is used when there is more than one delivery required for a supply that is not already set up in the call Sheet. It’s used to split deliveries of sand etc. when there is limited room at site.
Instructions – this option labels the split task with // Instructions so that a call out can be generated with additional instructions for the supplier / trade.
If a split task is requested on a task that is already scheduled, the Advance notice option is replaced by Callback which creates a new task with // Callback added to the task description. The communications to the Supplier is therefore identified as a Callback.
Schedule Task
allows you to go back to the schedule task to re-schedule the task for a different date or a different trade/supplier.
Create AdHoc Inspection
This allows you to schedule an inspection on demand, eg. a Site Safety inspection or similar.
Cancel Task (and Linked)
This will cancel a scheduled task, eg in case the job is not ready and you do not have an alternative date yet. This will send a cancellation notifaction to the trade/supplier of the task.
If this is a key task (task is highlighted in BLUE), you can also cancel all its Linked tasks as well.
Mark Complete (Today)
this will mark the task complete, if you chose compete, it will mark it complete immediately with todays date as its completion date.
Send Additional Instructions
This will generate an extra callup with additional instructions to the trade/supplier on the task, this is not to be confused with Split Instructions which also creates a separate Task. Send Additional Instructions does not create an extra task.
Requisition
Requisitions allows you to generate an ETS for this specific Task. This will then go through an internal Approval process before extra funds will be made available.
Add Custom Task after this task
If there is a need for a special task that is not part of the normal callup process, you can create a fully custom task by clicking this.
Send Callup to Supplier Now
If the taks is tenatively planned (using advanced Planner) the callup normally does not go out until the Notice Period is coming closer. You can expedite the sending of the callup by Clicking this.
More info on advanced planner here