I came across these Guides on the UK government site. The guides have explanations and real products for HS codes. It makes a lot more sense to read these guides to figure out where an item should be classified. I found the one for Computer Products very useful.
Although it is for UK small business, the HS Codes are universal for the first 6 digits which is what is needed for PayPal shipping labels for Canada Post.
Take a look and see if any are helpful. Post back any comments.
https://www.gov.uk/browse/business/imports-exports/classification-of-goods