Navigating Bricklink

So recently ive gotten into LEGO's big time. Been mostly into the Technic and modular sets for my wife that ive been picking up on eBay. I attempted to sell something on eBay and got myself permanently banned in a matter of minutes. Honestly, i have no idea what i did wrong. Called eBay immediately but no resolve. Ban was upheld. Seriously shocked. My buddy told me about Bricklink and it looks very cool. It looks like thats the site ill be visiting for my LEGO's but im having trouble...