A session is the actual roleplay that users can play with the AI. Session in astrsk.ai are created by selecting (character and plot) cards and a flow from the user's personal library.
Along with the cards and flow which the user selects from their personal collection, the user can also set local settings (background image, chat styling, language, etc) to enrich the roleplaying experience.
A flow is a set of agents that work together to create an AI response during a session. Flows dictate how the AI processes information and generates responses. One flow can have multiple agents; an agent is an entity that calls an AI model and contains an AI output as a result of the AI call.