You manage a product delivery organization.

Work with the Product Owner(s) to analyze current delivery capabilities against demand, then use that data to build a probabilistic forecast that serves to illustrate what might be achieved.

Use your knowledge to make the plan and later negotiate its implementation with the Scrum Team.

Work with specialists from each team to build an estimated backlog that you can translate into a Gantt chart.

Ask each Scrum Team to estimate the current backlog and make a plan against the story points previously delivered. Then normalize story points across teams to combine the estimates.