The Clients screen is your contact file, what marketing calls a CRM: the list of everyone who has left you their details, where each of them is in the process, and your appointment calendar with your available hours.

It is the screen you come back to every day to see who is new, who is due a call and what appointments you have. The full detail of how each contact arrives and what each stage means is in «A customer's journey: from ad to appointment».

The most common mistake when starting out is not moving people along the stages as they progress. If everyone stays in "Registered", the list stops telling you who is owed a next step from you.