AFAIK, there's not a single tutorial for scanning decks, because there's a ton of scanners and different TWAIN scanner interfaces, so it all depends on the one you're using. If Tarot decks are related, there's some advice I can give to you based on experience:
-Limit dpi size to 72 or 96 (screen size): bigger numbers just mean bigger cards and files, and Orphalese can't get advantage of this.
-Be careful on how you put cards on the scanner: a Tarot card is a tiny thing in size compared with a Legal Letter or A4 document. It can be tilted some degrees very easily, making a bad scanner.
-Try to get the same size for all cards, using the scanner interface or a post-processing graphic software. Orphalese can manage decks with different card sizes without problem, but you'll feel some dancing when dealing cards, very distracting when you're trying to do a serious Tarot job.
Any given Orphalese deck is just a bunch of graphics, you have to translate into Orphalese. There's a deck creation tutorial on my site,
www.tarotdiesirae.tk, in English and Spanish. Have a look and feel free to ask if doubt arise. Best.