Onion Net is a dark place, it not named dark for no thing. If you want to start a discovery down the hole, you would have to find some good guidance and map. For instance, you will need some certain tor device for browsing dark net safely, like tor browser and a lot more. Or, you would have to accept different habits for examining dark web, not to mark traces.
Hopefully there are some websites designed to guide you through complex world of underground deep web hidden from the surface. This one is the best one i know http://darknet-markets.site/
Darknet-markets.site - is an ultimate usher into the world of deep web.
It got what you need : most popular onion, the full guides for security, guide for onion marketplaces, onion reviews, new, updated and verified darknet markets onion links.