As above, the first two rakaats for example whilst the Imaam recites it aloud.As well as the third and fourth rakaat when the Imaam recites quietly.
According to the Hanafi Madhab, a Muqtadi (follower behind the Imaam) should
remain silent in the standing posture. It is not permissible to recite
anything in a standing posture behind the Imaam.
And Allah Ta’ala Knows Best
Mufti Ebrahim Desai