Your setup checklist
Setup gave you a working org. This is the short list that turns it into your business, roughly an afternoon, in the order that avoids rework.
Get the foundations right
Put your week on the calendar
Add a recurring schedule for each regular class and let Zenly fill every future week, and publish your bookable hours for anything 1:1. The two guides are Create a recurring class and Offer appointment time slots.
Bring in your people
Add your staff with the role each one needs, then add your existing clients and sell them the plan they are already on. Members claim their own portal login whenever they are ready, so there is nothing to send; see How clients get their login.
Take one booking end to end
The last step is the one people skip. Sell yourself a plan, book a seat, check in, then open your reports and watch the numbers move. Ten minutes here catches the wrong timezone, the plan that covers nothing and the class nobody can book, while it is still only you looking.