Okay, I think you just needed to add David’s CSS and HTML assets.
I added them and I get the nicely styled toggle switch and output that likely means it is working.
Clone to demonstrate (note that you may have to adjust your dependency name to match):
https://anvil.works/build#clone:ASLFGNAVOW4UXHY3=D6EC73PSZZQSNKGEPBWFS3XF
I hope this helps.