Get the hours from an appointment as an Array

Interestingly, you can't get time data very easily in Ninox. You can get the start()/end()/duration() of an appointment field.

Even with time fields, there is no command like month or day that will get the hour or minutes of a time field.

I can see the desire for a visual representation of availability, but it seems like a lot of work that we can get to the same data in some other way.

It all depends on your how your dashboard is designed. So let's say you are assigning workers to an event (could be skipper or engineer or steward or anyone needed). So you select the event. The event already has day(s) assigned to it. In your dynamic choice field for Skipper (since there is only 1) you can only show skippers that aren't working that day. For positions with more than 1 worker you could use a dynamic multi choice field. Then you have a button that assigns the workers to the Event subtable Scheduled Workers.

let ast := start(Appointment);
let aen := endof(Appointment);
if day(ast) = day(aen) then
    range(number(format(ast, "H")), number(format(aen, "H")) + number(format(aen, "m") != "0"))
end