I cannot help with your type (Atr 72-500??)
but generally it will depend on which instrument you are using.
If you are merely using an ILS indicator display, you would need either a 'Back Course' switch or to reverse what you do. This is because the instrument
only knows whether you are left or right of the beam.
If you have the ILS displayed on an HSI, the HSI
'knows' the direction of the beam you are trying to follow (you set it in a window somewhere) and thus will know how to display the deviation so it is displayed correctly.
Edited to add 'Inbound course' set on the HSI