Hi Julian - 

To ensure that the Project Start-up milestone appears at the start of the project in the workplan view, you can manually position it by using the 'drag and drop' feature in the Roadmap. This allows you to place the milestone at the desired location, such as the beginning of the project timeline.

Regarding specifying the sequence order of new work items in relation to existing items, you can create dependencies between work items. The default dependency type is Finish to Start, but you can select other types such as Start to Finish, Finish to Start, etc., by choosing the Dependency Type field when setting up the dependency. This allows you to control the order in which tasks or milestones occur relative to each other in the project hierarchy. 

Resources for reference -
Work Management Milestones - https://success.planview.com/Planview_AdaptiveWork/Work_Item_Management/Milestones
Business Rule Config - https://success.planview.com/Planview_AdaptiveWork/Configurations/Business_Rules

Thanks for the reply, Aayush. I think that you are suggesting that once the project is created using a workflow, the user should manually position it at the top of the project. I was trying to avoid having to train all my users to do a manual repeated step and was wanting to do this through configurations.

The sequence order I am talking about is not the dependencies, but is just the order work items appear in a project workplan view. However if the display ordering I need can be controlled by setting dependencies, then I can try to add some dummy dependencies to see if it accomplishes what I need  e.g. all milestones have a dependency on the Project Start-up Milestone being started.     

Yes, You're right! Julian! Here's what I can confirm - 

• The “Sequence Order” field for tasks and milestones can be displayed as a column in the workplan, but it cannot be controlled or set directly by workflows or configurations. You can specify a parent when creating a work item by custom actions, but not its explicit placement in the sequence or row order—manual repositioning is still needed if you want a milestone to appear first.
• The order of items in the workplan is not determined by dependencies; adding dependencies (even dummy ones) will not force work items to display in a particular order. Dependencies work for scheduling and relationships, not for display order in the workplan view. 

In summary - It is not possible to automatically position a new milestone or task at the top (or any specific location) in the project workplan display order through configuration, workflow, or by manipulating dependencies. Manual adjustment remains necessary.