Explanation
A permission set group is a collection of permission sets that can be assigned to users as one unit; it simplifies permission management by reducing the number of permission assignments needed for users who require multiple permission sets. A permission set is a collection of settings and permissions that give users access to various tools and functions in Salesforce; it can be used to extend users' access beyond their profile without changing their profile. Creating permission sets and assigning permission set groups can help Cloud Kicks give access to new custom object with custom fields to more than one user by creating permission sets that include access to new custom object with custom fields and assigning permission set groups that contain those permission sets to users who need them. Adding users to manual sharing list or editing organization-wide defaults are not options for giving access to new custom object with custom fields to more than one user; they either do not apply to custom objects or do not grant object-level access. References:
https://help.salesforce.com/s/articleView?id=sf.perm_sets_overview.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.perm_set_groups_overview.htm&type=5