You already understand allotments. Your shop got two copies of a hot issue and twelve of the rest. A mint window is that, without the shop’s front counter. The publisher decides how many editions exist. You either claim one in the hour or you look later on a secondary listing, the way you once hunted a back issue in a long box.
You do not need to care about chains as a subject. You need a wallet you can open, a listed price you can pay, and a file you can read. Everything else is furniture. If a friend insists you must also join a forum, you may ignore the friend.
The part that is genuinely new is the lack of a physical damaged-copy bin. There is no half-price copy with a creased corner. There is also no browsing. You decide from a cover and a synopsis, the way mail-order comics once asked you to. That is why we write issue dossiers: so the decision is about the story window, not about a countdown you should not trust.
If you leave a drop empty-handed, the run is not gone. Later listings appear. Anthology packs reprint. Reading-order sessions exist so you can keep going with paper while you wait, which is what most Wednesday-shop readers already wanted.