en_tn_condensed/act/19/29.md

The whole city was filled with confusion

Here "city" refers to the people. The city is spoken of as if it were a container. And, "confusion" is spoken of as if it were the contents that filled the container. Alternate translation: "Then people all over the city became upset and started shouting" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-metaphor)

the people rushed together

This was a mob or near riot situation.

into the theater

The Ephesus theater was used for public meetings and for entertainment such as plays and music. It was an outdoor semi-circular area with bench seats that could hold thousands of people.

Paul's travel companions

The men who had been with Paul.

Gaius and Aristarchus

These are names of men. (See: rc://en/ta/man/translate/translate-names)