The Prophet ﷺ used to deliver two sermons. He would sit down when he ascended the pulpit till he (I think he meant the mu'adhdhin) finished. He would then stand up and preach, then sit down and say nothing, then stand up and preach.
كَانَ النَّبِيُّ ﷺ يَخْطُبُ خُطْبَتَيْنِ كَانَ يَجْلِسُ إِذَا صَعِدَ الْمِنْبَرَ حَتَّى يَفْرُغَ أُرَاهُ قَالَ الْمُؤَذِّنُ ثُمَّ يَقُومُ فَيَخْطُبُ ثُمَّ يَجْلِسُ فَلاَ يَتَكَلَّمُ ثُمَّ يَقُومُ فَيَخْطُبُ
The Prophet ﷺ used to deliver two sermons. When he ascended the minbar (pulpit), he would sit until the muʾadhin finished the call to prayer. Then he would stand and deliver the sermon. Afterward, he would sit and remain silent for a while, and then stand again and deliver the second sermon.
It has been narrated to us through the ḥadīth of Isḥāq b. ʿAbdullāh b. Abū Ṭalhah from Anas b. Mālik regarding the story of the pulpit. He said, "A minbar with two steps was built for him, and he would sit on the third step. When the Prophet ﷺ sat on it, the trunk of the date-palm tree moaned."
كَانَ النَّبِيُّ ﷺ يَخْطُبُ خُطْبَتَيْنِ كَانَ يَجْلِسُ إِذَا صَعِدَ الْمِنْبَرَ حَتَّى يَفْرَغَ أَرَاهُ الْمُؤَذِّنُ ثُمَّ يَقُومُ فَيَخْطُبُ ثُمَّ يَجْلِسُ فَلَا يَتَكَلَّمُ ثُمَّ يَقُومُ فَيَخْطُبُ وَرُوِّينَا فِي حَدِيثِ إِسْحَاقَ بْنِ عَبْدِ اللهِ بْنِ أَبِي طَلْحَةَ عَنْ أَنَسِ بْنِ مَالِكٍ فِي قِصَّةِ الْمِنْبَرِ قَالَ فَصَنَعَ لَهُ مِنْبَرًا دَرَجَتَيْنِ وَيَقْعُدُ عَلَى الثَّالِثِ فَلَمَّا قَعَدَ النَّبِيُّ ﷺ عَلَى ذَلِكَ خَارَ الْجِذْعُ