Make sure you have in the backed a confidential group.
Then follow the following steps to configure your form:
Step 1:
1) Enable Keyword: Readers Field Setup.

1) In This menu select relevant confidential groups that were set up in the back end.
(Recommendation: Include Superusers group too). Enable the readers field (yes)

Step 2:
Configure the form:
1) Select Template form Library:

2) Select Edit:

3) To make the form confidential select Yes to question: Confidential (Yes) As highlighted below.

4) Option: What is the default setting of Confidentiality? (Public or Private)
Note:
Private: If you make it private all your forms (in this case the incident forms are become confidential, only people involved and part of the confidential group will be able to see the form)
Public: If you make it public (the forms will become confidential once you select option Make it Confidential/security)
5) Select viewing groups as shown in picture above. (ex. ABP Confidential, GFP Confidential, GFP Superuser)
6) Go to Workflow wizard

7) From the library drag security Button and placed into the forms action list.

8) Save the changes:
Step 3:
Raise form and test Functionality:
When you create a form and the default is set to public the form is public unless you make it confidential.

To make it confidential Select confidential and relevant group that should see form (groups shown are the one preselected on template)

If forms are set by default to private, all forms will become confidential.
(See attached file: QuickGuide to Enabling Confidentiality in Smart forms.docx)