Explanation:
Box 1: Assign Create and Read rights to activities
For Create task, User needs read permission also.
Box 2: Assign organization--level assign rights to the human resources case table.
Assign organization level assign rights. They need to be able to assign cases to other users. It could be a case that anyone owns.
Reference:
https://docs.microsoft.com/en-us/power-platform/admin/security-roles-privileges
https://docs.microsoft.com/en-us/power-platform/admin/wp-security-cds