Many salons run on a mix of a paper diary, WhatsApp, a till and a shoebox full of receipts. Here is how to bring it all back into one system, without closing for a week.
First gather all your customer details in one place. Import what you have, even if it is incomplete; you can fill in the gaps at their next visit.
For each service, record the duration, the price and the staff members who perform it. This is the foundation of your online calendar: if this is wrong, nothing after it will be right.
Run both for two weeks. You will see where things rub without any risk, and you build confidence in the new system.
Once your calendar is right internally, open the widget to customers. The other way round does not work: you end up fixing mistakes while your customer is watching.
Cancel within the trial and you pay nothing.