How do I set permissions for a salesforce group?

Follow the steps below to assign Permission Set Groups to Users :
1. In the Permission Set Group detail page, click Manage Assignments.
2. Select each user who you want to assign the group to, and then click Assign.
3. Click Done.
4. To remove a user from the permission set group assignment, select the user name, and click Remove Assignments.
5. Click OK to confirm the removal, and click Done.