Can I use a Commandline?
Yes. You can use a commandline. You do so with switches.
But before you do you should fill in the settings through the GUI. This will let you do the signing easily with just this command:
ecs /p:[product.exe]
The available options are:
/p: - Where the file to be signed is located
/t: - the timestamp url - overrides value in settings
/n: - the program name
/c: - the certificate - overrides value in settings
/s: - the certificate password - overrides value in settings
/i: - information url - overrides the value in settings.
You should not leave a space between the switch and the value. Spaces is the way the commandline is split and then processed.