فَإِذَا صَعِدَ الْإِمَامُ الْمِنْبَرَ: جَلَسَ، وَأَذَّنَ الْمُؤَذِّنُونَ بَيْنَ يَدَيِ الْمِنْبَرِ، ثُمَّ يَخْطُبُ الْإِمَامُ.
Translation: When the imam ascends the minbar he sits, the callers give adhan before the minbar, and then the imam delivers the sermon.
The imam sits on the minbar, the adhan is called before him, and the sermon follows. The earlier public announcement and the call associated with the minbar have distinct places in the Friday sequence.