I don't have project so I couldn't test this but you can loop through the code with F8 to see what needs fixing.
Use it in a testing phase first.
Sub Export_Selection_To_OL_Appointments()
'project variables
'I used object because I don't have project
    Dim myTask As Object
'outlook variables
    Dim myOLApp As Object
    
    Dim Ns As Object
    Dim folder As Object
    Dim appt As Object
        
'setting up outlook for appointment in shared calendar
'myOLApp = outlook
'ns = outlooknamespace environment
    Set myOLApp = CreateObject("Outlook.Application")
    Set Ns = myOLApp.GetNamespace("MAPI")
'the shared calendar is part of your default calendar = folder of folder
'B2A Projects Calendar = name of shared calendar ?
    Set folder = Ns.GetDefaultFolder(olFolderCalendar).Folders("B2A Projects Calendar")
'appointment should be added to shared calendar
'so for every task in your selection we make an appointment in shared calendar
    For Each myTask In activeselection.Tasks
        Set appt = folder.items.Add
        With appt
            .Start = myTask.Start
            .End = myTask.Finish
            .Subject = " Rangebank PS " & myTask.Name
            .Categories = myTask.Project
            .Body = myTask.Notes
            .Display 'or .Save
        End With
        'clear the appt variable to accept new values for next myTask
        Set appt = Nothing
    Next myTask
'clear up variables
myOLApp = Nothing
End Sub
Charlize