You do not need to upgrade to full CamPlus unless you want full length video and no cooldown time.
If you are OK with 12 second video events and a 5 minute cooldown between events, all you need is CamPlus Lite which can be free.
Go to this Topic and start with the video at the top.
Yes, at a minimum you should have thumbnail photos. If you do not, something is not working right. As for getting that if it is not there, I can’t answer that. If you have an SD card recording, you should be able to click the playback to see the footage on the card that triggered the event.