Hi @drewwiseman,
If the Advanced Roadmaps is used, you need to import Parent Link and Epic Link fields and then after the data import “Advanced Roadmap” hierarchy is created based on the Jira configuration (on the Cloud you need to enable the integration and add the hierarchy configuration, see here).
Also, in this Community article you can learn more about additional issue hierarchies.
After that you can create a custom measure in the Measure dimension to roll up the progress. See an example here using “Issues resolved %”: Issue Epic Gantt Chart - Issues - Jira Demo - eazyBI
Kind regards,
Gerda // support@eazyBI.com