After pressing Enter, you will be taken back to the Key Management Menu. Select option 6 to create a self-signed certificate, and then select option 1 on the next menu to create a CA certificate. In this example, the CA certificate will be called "example_ca".
Select the options that are appropriate for your needs in the next menus. For this example, we create a 2048 bit RSA key and use a SHA-256 signature.
Return to the Key Management Menu with option 1. Select the newly created certificate: