Prophet Muhammad worship in Cave Hira

As per this hadith, https://sunnah.com/bukhari:3 it is mentioned that **"He used to go in seclusion in the cave of Hira where he used to worship (Allah alone) continuously for many days before his desire to see his family."** My question is what Prophet used to do in the cave as there was no concept of namaaz at that time. How and what he used to worship? Which surah and whatever relevant Prophet used to speak in the worship? What was his day like in the cave?