If you want to have the erasure started on bootup of the software you need to change the (sample-)wd-options.cfg file, those settings are not in the GUI.
In the sample-wd-options.cfg you can find the below below text, please change and/or copy this to the wd-options.cfg file.
# Only applies to cloud activated version of WipeDrive. You can supply your
# cloud activation code below to avoid being prompted at the start of each wipe.
# Code format is: XXXX-XXXX-XXXX-XXXX
cloud-act-code=[ADD YOUR CLOUD CODE]
# Set the number of times the user should be prompted to confirm a wipe
# operation prior to starting. Valid values are 0, 1, or 2.
# By default WipeDrive prompts the user to select which drives they would like
# to wipe. This option takes the index number of the drive you would like to erase.
# The value -1 means all drives. The drive index starts at 0 and increments for
# each available drive in the system. There is no guarantee that a particular
# drive will have a particular index number. Therefore, unless you're wiping all
# drives, it's recommended to leave this disabled.
== If you prefer you can copy only the last lines to the wd-options.cfg file
Save this in to the wd-options.cfg file and add it to the ISO. It will now start the erasure on all drive after the software is booted. Of course only if you have the custom fields prompting AFTER the erasure. Otherwise you need to add this information first.
If you need help or advise from our support team, please email us at firstname.lastname@example.org