The details of the trial license can also be passed to iSpring SDK through this Command Line interface:
iSpringSDK.exe a "QJ0K7-Y8H10-CSG6C-GP688-P49R9-FBF4H-T15CG-J040M-DPSGJ-CGJ99"
C#
As soon as the trial license is successfully activated, you'll receive a message to that effect.