Creating a private 'Service Codes' group will allow you to easily find your private codes when creating invoices. To create a group, go to Preferences in the left hand menu, and Service Codes:
a. Enter a group name, then click the green "Create new group" button.
b. Your new group will appear in the list above. It is currently empty, though. To add codes to this group, click on the blue Edit pencil icon:
This will bring you to the following page:
c. On the right side of the page, 'search for service codes' you want to add to your group (highlighted field below). Once found, click on the green "+" button to add it to your list (red square in example below):
d. Review your group on the left side, delete any unwanted codes (use the garbage can icon). When you are satisfied with your group, click on blue "Update Group" button to save.
e. To have your private 'service code' group display automatically in your billing window (in the Create Invoice section) when you select the private billing option (Invoice Type), go back to the Service Code page, and click on "Set as Private Primary" for this group.
Your group will now be set as "Private Primary" in green, as shown below.