The A320 will happily fly right past TOD and it will not start a descent even if a lower altitude has been set. You need to start the descent yourself. The only trigger you get is a weird «deselerate» message to remind you.
The approach mode engages automatically, except when it doesn’t. You may have to select it yourself.
You will not even get the ILS indications unless you press LS, even if the correct approach has been loaded and frequencies checked.
Some aspects of this aircraft are not user friendly.