Before LinketySplit will sell access to anything on your site, two things need to be in place: LinketySplit has to know you actually control the domain, and each article needs a price.
Add your domain from your publication's dashboard, then prove you control it with whichever of these is easiest for your setup:
<meta> tag into your site's <head>.Whichever method you pick, verification runs a check against your domain and flips it to verified once it finds what it's looking for. DNS changes in particular can take a few minutes to propagate, so a failed check right after adding a TXT record usually just means "try again shortly."
Your dashboard's pricing settings set the price LinketySplit charges for any article on your domain that doesn't specify its own — a single default price for one copy of access, with no per-article setup required to get started.
You can also add discount tiers to that default — a lower per-copy price once a reader buys a certain quantity at once. A reader buying five copies to share with colleagues, for instance, might pay less per copy than someone buying just one for themselves. Tiers are entirely optional; plenty of publications ship with a single flat default price and nothing else.
An individual article can override the default with its own price by carrying a bit of markup on its page — see Using the API and SDK for how that works, and for how a purchase link actually gets created once a domain is verified and a price is set.