Explanation
Box 1: Hierarchy
Hierarchy: Users in a specific organizational hierarchy.
* After you select Hierarchy, on the Hierarchy selection tab, in the Hierarchy type list, select the type of hierarchy to assign the step to.
* The system must retrieve a range of user names from the hierarchy. These names represent users that the step can be assigned to.
Box 2: Participant
Participant: Users who are assigned to a specific group or role.
After you select Participant, on the Role based tab, in the Type of participant list, select the type of group or role to assign the step to.
In the Participant list, select the group or role to assign the step to.
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/organization-administration/configure-appro