No more Haloscan, but Disqus is giving me a headache

For some reason I didn't realise that Haloscan had already gulung tikar (ceased to exist; effective last week), which might explain the dearth of comments...

So I decided to try Disqus, but I can't figure out how to manually install it with my template because it's not the new standard XML template, but the old school HTML "classic" confusing (to me) template. Tried following these instructions, but still nothing (on my end).

While I am still trying to work this one out, please bear with me.

Thank you.