Can't Monitor Oracle Database

I need to monitor database each instance step by step but I can't find screen New Monitor I use Opmanager version 5.6

1. Click the New Monitor.

2. From Add Monitor of type combo box, select Oracle DB Server.

3. Enter the IP Address or hostname of the host.

4. Enter the SubNetMask of the network.

5. Enter the port number in which the Oracle is running.

6. Enter the polling interval time in minutes.

7. Provide the user name of the admin user ('system' is the default username) and its corresponding password.

8. Provide a valid Database name.

9. Choose the Monitor Group from the combo box with which you want to associate Oracle database server Monitor (optional).

10. Click Add Monitor(s). This discovers Oracle database server from the network and starts monitoring them.