To create or view the Portal user group, navigate to: Admin -> Admin -> Customer Portal User Group. 
Click on ‘Customer Portal User Group’ to create a Portal User Group and you will be redirected to the ‘WordPress User Group’ Module’s List View. 
Here, you can see ‘Default’ WordPress User Group already exists in the list. User cannot delete this ‘Default’ group record. Admin user can create different ‘User Groups’ and define accessible modules for that group.
Note: By default, ‘Default’ group will be assigned to a newly created contact record.
On the left panel, by clicking on ‘Create Portal User Group’, you can create a User Group with Description.
After inserting ‘Group Name’ & ‘Description’, Save it.
You can tick the ‘Is Primary Group’ option if you want to select this User Group as Primary Group. 
Note: Only one User Group can be selected as ‘Primary Group’.
By clicking on the Group Name from the list, the detail page will be opened as shown below.
Under the “Portal Access Module List”, you will get the Relationship Type to define the relationship of the selected user group. You can select either Contact based, or Account based.
If you select Contacts, the portal user will get the data that is directly related to the Contact. But if you select Account, the portal user will get the data that is related to Contact’s Account.
Relationship selection is provided to select the relationship for the module with contacts or accounts. The relationship of the modules will be changed as per the selection of the Relationship Type. 
Enable the Modules from here and give the rights for Create/Edit/Delete/Subpanels by ticking the options to your customers.
It means the user will get the access to the module as per your settings.