Here are the steps requires to add interface methods:

1. The first step is to add GetPhoneRec to interface IReadPhBook. Right-click on IReadPhBook in the ClassView pane of the Workspace window.
2. Click Add Method ... to bring up the Add Method to Interface dialog.
3. In the Add Method to Interface dialog, type GetPhoneRec for the method name. Type [in] PhRec *pPhRec, [out] BOOL *pOK as parameters. Normally, the implementation is displayed in the Implementation window as you type. When you are done, click OK.
   
4. We have expanded IReadPhBook in Class View to show GetPhoneRec as a member of IReadPhBook. The next step is to add AddPhoneRec to IManagePhoneRec. Right-click on IManagePhBook.
5. Click Add Method ... to bring up the Add Method to Interface dialog.
6. In the Add Method to Interface dialog, type AddPhoneRec for the method name. Type [in] PhRec *pPhRec, [out] BOOL *pOK as parameters. Normally, the implementation is displayed in the Implementation window as you type. When you are done, click OK.
7. We have expanded IManagePhBook in Class View to show that AddPhoneRec has been added. The last step is to add DeletePhoneRec to IManagePhBook. Right-click on IManagePhBook.
8. Click Add Method ... to bring up the Add Method to Interface dialog.
9. In the Add Method to Interface dialog, type DeletePhoneRec for the method name. Type [out] BOOL *pOK as parameters. Normally, the implementation is displayed in the Implementation window as you type. When you are done, click OK.
10. Class View displays DeletePhoneRec under IManagePhBook. This is the end of the simulation.