This photo shows one of the castles made - in this case, cut out and assembled by an 8 year old with limited help from me.
The first picture shows the general layout. The walkways and drawbridge were on the card template and were drawn in the same way as the decking for my Tealight Ironclads article a couple of years back in Miniature Wargames with Battlegames issue 366. The pyramid shapes on the towers were taken from nets on the SEN Teacher website
This closeup shows the simplified drawbridge. The gate was a piece of clipart from the Internet.