È is the third-person singular present tense of essere (to be).
The subject is l’attrice, which is singular, so Italian uses è:
This is exactly like English she is or the actress is.
Già means already.
It shows that the actress is on stage before the curtain opens. So it adds the idea of something having happened earlier than that later moment.
In this sentence:
Italian often places già before the phrase it modifies, much like English already.
Sulla is a contraction of:
So:
This happens very often with Italian prepositions plus definite articles:
So sulla scena literally means on the stage/scene.
Italian often uses the definite article where English may or may not use one.
Here la scena refers to a specific stage or performance setting, so the is natural in Italian:
Even when English is a bit flexible, Italian often prefers the article.
Literally, scena can mean scene, but in this context sulla scena usually means on stage.
So while the word is related to English scene, the phrase here refers to the physical performance area.
That is why learners should understand the whole expression:
Context is important, because scena can have several meanings in Italian.
It looks reflexive, but here it is better understood as the curtain opens or opens up.
The verb is aprire (to open), and aprirsi can be used in Italian for something that opens by itself or is presented as opening:
So si does not mean the curtain is literally doing something to itself in a fully literal English reflexive sense. It is a very normal Italian way to express that something opens.
Italian often uses the present tense to describe actions in a scene, a plot summary, or a general sequence of events.
So this sentence can describe what happens in a play or what is happening in a dramatic moment:
English can do something similar:
So the present tense here is completely natural.
Because quando here refers to a real, concrete event: when the curtain opens.
Italian normally uses the indicative after quando when talking about real events or usual sequences:
You would not normally use the subjunctive here.
Yes. Italian allows some flexibility in word order.
For example, this is also correct:
This version puts the when clause first. The meaning stays basically the same.
The original version is also very natural because it starts with the main point:
A few small things:
A rough guide to the whole sentence is:
lat-TREE-che eh jah soo-la SHAY-na KWAHN-do eel see-PAH-ryo see AH-pre
Not perfect English-style phonetics, but enough to help a learner.