How to set the tag property for a resource or allocation.

Use something like this:

var
  resource: TssResource;
  allocation: TssResourceAllocation;
begin
  // add a new resource and get a reference to it
  resource := RAC.AddResource('Ballroom', clRed);
  resource.Tag := 1;

  // add a new allocation and get a reference to it
  allocation := resource.AddSlot(Now, Now + 1.0);
  // in case the allocation could not be created
  if allocation <> nil then
    allocation.Tag := 2;
end;