Unexpecting turn. Please, correct my mistakes

A theatre. 

There are lots of people sitting on the chairs of tribune. There is a table located in the center of the arena with a candle on it. It's dark in the theatre and then a man appears there. He comes to the table and he sits down on the chair.  He lits up the candle, opens a magazine and begins jerking off.

Then one of spectators makes a sound:
"Hm-hm!"
"Uh! What!? Who is here!?" Whispers a man

Unexpecting turn. Please, correct my mistakes

A theatre. There are lots of people sitting on the chairs of tribunes (did you mean in the stalls? https://theatre.london/theatre-guide/beginners-guide-sit-theatre/). It's dark in the theatre. There is a table with a candle on it (I'd better say "a candle-let table") located in the center of the arena (you meant a stage?). Then a man appears. He comes to the table, sits down on the chair (or simply sits on the chair).  Then he burns the candle, opens a magazine and begins jerking off.
Then, one of the spectators makes a sound:
"Hm-hm!"
"Uh! What!? Who is here!?", whispers a man.