
Explanation
Box 1: Create a new team, and the business unit users, and the assign the security role to the team.
Change the business unit for a team
Important
By changing the business unit for a team, you can remove all security role assignments for the team. At least one security role must be assigned to the team in the new business unit.
Select an environment and go to Settings > Users + permissions > Teams.
Select the checkbox for a team name.
Screenshot selecting a team.
On the menu bar, select Change Business Unit.
In the Change Business Unit dialog box, select a business unit. Enable Move records to new business unit to move to a new business unit. Select OK.
Box 2: Grant the user a security role from the child business unit.
Reference: https://docs.microsoft.com/en-us/power-platform/admin/create-edit-business-units
https://docs.microsoft.com/en-us/power-platform/admin/security-roles-privileges