folder share workflow question

For a public folder, do I set the permissions at the Folder share level, or in the Security tab?

Parent

-Child01 (DL_SecGroup01), (DL_SecGroup02)

-Child02 (DL_SecGroup01)

-Child03 (DL_SecGroup01), (DL_SecGroup02)

When setting up shares

Parent>Properties>Sharing>Network File and Folder Sharing, do I add the users (Domain Local security groups) at this step, or just share to everyone (Domain Users > Read) and then set security permissions on Child01, Child02, Child03?

Thanks