وَالصَّلَاةُ عَلَى الْجِنَازَةِ أَنْ يُكَبِّرَ تَكْبِيرَةً، يَحْمَدُ اللَّهَ تَعَالَى عَقِبَهَا.
Translation: The funeral prayer begins with a takbir, followed by praise of Allah.
ʿAqibahā means “after it”: praise follows the opening takbir. In Hanafi practice the opening praise (thanāʾ) is recited here.
This is the first of four takbirs, not a separate preliminary takbir added to four more.