Hello watain,
How you charge taxes will depend on how you incorporate your business, whether you incorporate it provincially or federally. It's a bit complicated but I think you'll find our Link hidden: Login to view helpful.
Also, I've answered a few questions regarding Canadian taxes and importing duties on this post - Link hidden: Login to view
It is still best to seek professional help from an accountant should things get too complicated for you.
Hope this helps :)