To provision a new device certificate, navigate to Device Certificates on the navigation sidebar of your Server Management page. Click Provision Device Certificate on the Security Management page. You will be taken to the form afterwards.
Select the Device and Signing Certificate of your device certificate from the drop-down menus, and then key-in the Validity Period of your certificate.
Note: There's no minimum number of days for the validity period of your device certificate. However, it should not exceed with the validity period of the server certificate associated with it. For example, if you set your server certificate's validity to 7 days, then your device certificate should be set to 7 days below.
Once all fields are complete, click Create Device Certificate. You should be able to see a notification saying that your device certificate has been created. The system will also automatically download a zipped file containing the device certificate and keys.