You would be responsible for customs, shipping and dealing with the foreign company...If there were issues with the products, you would/could also be held liable for that. That's part of what your buyer is paying for.

I don't think it's impossible to find decent trade/suppliers online...but you better be quite the networker and know people who know people overseas. Like you already said, that magic e-book with all those untapped suppliers doesn't really exist...

I can't imagine just jumping into a market and expecting to go far without a lot pre-market research and knowledge.