The meeting date range determines how far into the future the client can book the meeting. Here are the options.
Number of days into the future: This determines how many days into the future the client can book a meeting.
Within a date range: Specify a start and end date to set the active period for the meeting. Both the start and end dates are inclusive. This will ensure your client can book a meeting only within the given date range.
Indefinitely into the future: This allows your clients to book a meeting way into the future. Be careful with this option.
As you change the meeting schedule options, you will observe the corresponding updates on the calendar shown on the right side of the screen.