I have a development project with a WBS like this:

Can you please advise me what would be the best structure ?
How cand I best map, Phase , Sub stage, Phase , Activity and Task?
I thought like this:
- Phase -> Plan
- Sub stage -> Board
- Activity -> Task
- Task -> Sub-task
Would that be correct? Is there a better way?
Also, can I configure a bulk import for everything or only tasks and sub-tasks?
Thank you dearly for all your support.
Kind regards,
Gina