Keys apply to direct purchases only - store purchases need none. Open Help > Getting Started and enter the key there, or paste it under Settings. The app validates it immediately and the licensed apps and providers unlock.
A direct-purchase key is named: it lists the built-in providers (Sprint Logistics, ShipHero, Amazon MCF), the capability packs and the custom provider slots your order covered. A named provider allows any number of its instances, with staging and live sharing one entitlement; custom slots count distinct swagger-defined provider definitions.
Bought another adapter or pack later, or need a slot added? LataSys amends your license centrally - there is no new key to install and nothing to reinstall. Changes apply automatically on the next daily license check. Help > About always shows what your license currently includes.
Without a key the app runs in evaluation mode, so you can install it, connect a sandbox and explore before buying. Enter a key at any point and the installation becomes fully licensed in place - nothing to reinstall, nothing lost.