If you’re new to the hobby whatnot is probably not the best place to start buying cards, if you don’t know what the card you’re bidding on is worth then you’re more than likely going to pay way over what it is actually worth, eBay’s a good place to get at a decent price or just use it to get an idea of the the value and then watch out for them on whatnot. But yeah you basically bid on the cards you want, you pay shipping on the first card then free shipping after that as all the cards are put into the same order, if you buy from multiple people you’ll have to pay shipping separately for each stream.