72 Grk “he”; the referent (Herod) has been specified in the translation for clarity. Herod was Herod Agrippa I, the grandson of Herod I (Herod the Great).
73 Or “apparel.” On Herod’s robes see Josephus, 19.8.2 (19.344), summarized in the note at the end of v. 23.
74 Although βῆμα 3 gives the meaning “speaker’s platform” for this verse, and a number of modern translations use similar terms (“rostrum,” ; “platform,” ), since the bema was a standard feature in Greco-Roman cities of the time, there is no need for an alternative translation here. The judgment seat (βῆμα, bēma) was a raised platform mounted by steps and sometimes furnished with a seat, used by officials in addressing an assembly or making pronouncements, often on judicial matters. The judgment seat was a familiar item in Greco-Roman culture, often located in the agora, the public square or marketplace in the center of a city.
75 Or “delivered a public address.”

In other versions

On an appointed day Herod put on his royal robes, took his seat upon the throne, and delivered an oration to them.

On the appointed day Herod, wearing his royal robes, sat on his throne and delivered a public address to the people.

On an appointed day, dressed in royal robes and seated on the throne, Herod delivered a speech to them.

and an appointment with Herod was granted. When the day arrived, Herod put on his royal robes, sat on his throne, and made a speech to them.

So on an appointed day Herod, after putting on royal clothing and sitting down on the judgment seat, began to deliver a public address to them.

And upon a set day Herod, arrayed in royal apparel, sat upon his throne, and made an oration unto them.

Public Domain