How does a team calculate its initial velocity during its first PI Planning meeting when teams don't have historic data?

SAFe’s guidance for new teams without historical velocity is to assign 8–12 points per team member

(typically 10) except Scrum Master and Product Owner, subtracting points for planned absences.

“For initial velocity, a simple guideline is to assume 8–12 points per team member (excluding Scrum

Master and Product Owner), then subtract 1 point for each day of vacation or holiday.”

(Source: SAFe 6.0 Framework: PI Planning Preparation)