Generate Series from today

Can you post a depiction of the expected result? At the moment the code delivers a table with time values, right?

Edit: see if this works for you:

Appointment Times with date =
VAR Opening = 9
VAR Closing = 17
VAR TimeSlot = 30
VAR Offset = ( TimeSlot / 2 )
RETURN
    GENERATE (
        GENERATESERIES ( 0, 1439, 1 ),
        // 24 hours/day * 60 minutes/hour = 1,440 - 1 (initial time 12am) 
        VAR __Minutes = [Value]
        VAR __Time =
            TIME ( 0, __Minutes, 0 ) // MROUND: Rounds Value to the nearest multiple of TimeSlot
        VAR __MinutesRounded =
            MROUND ( ( __Minutes + Offset ), TimeSlot )
        VAR __StartTimeSlotRounded =
            TIME ( 0, __MinutesRounded - TimeSlot, 0 )
        VAR __EndTimeSlotRounded =
            TIME ( 0, __MinutesRounded, 0 )
        VAR TimeValues =
            ROW (
                "Hour", HOUR ( __Time ),
                "Minute", MINUTE ( __Time ),
                "Hour Minute 24h", FORMAT ( __Time, "hh:mm" ),
                "Hour Minute 12h", FORMAT ( __Time, "hh:mm AM/PM" ),
                "30 Minute Slot Start", FORMAT ( __StartTimeSlotRounded, "hh:mm" ),
                "30 Minute Slot End", FORMAT ( __EndTimeSlotRounded, "hh:mm" ),
                "30 Minute Slot",
                    FORMAT ( __StartTimeSlotRounded, "hh:mm" ) & "-"
                        & FORMAT ( __EndTimeSlotRounded, "hh:mm" ),
                "Working Hours",
                    IF (
                        ( __Minutes / 60 ) >= Opening
                            && ( __Minutes / 60 ) <= Closing,
                        "Yes",
                        "No"
                    ),
                "Time", __Time,
                "TimeSlot Start", __StartTimeSlotRounded,
                "TimeSlot End", __EndTimeSlotRounded
            )
        VAR Day2 =
            TODAY () + 2
        VAR Calend =
            CALENDAR ( TODAY (), Day2 )
        RETURN
            ADDCOLUMNS (
                CROSSJOIN ( Calend, TimeValues ),
                "DateTime",
                    FORMAT ( [Date] & " " & [Hour Minute 24h], "General Date" ),
                "DateTime Start",
                    FORMAT ( [Date] & " " & [30 Minute Slot Start], "General Date" ),
                "DateTime End",
                    FORMAT ( [Date] & " " & [30 Minute Slot End], "General Date" )
            )
    )

which gets you this (showing the last columns including the date)