Obtain a full copy of the script as photocopies for actors usually leave out the bits we need.
You are looking for:

List of scenes which may give you an idea of how many different lighting states or looks may be needed.

Scene synopsis will provide a summary of each scene, possibly with time and location information.

Script – dialogue for actors that may include information for lighting such as dark stormy night.
Props list. The playwright may include stage directions for actors movement or actions such as turn a light on or off.

Stage plan to show areas actors use.

Lighting cues – some authors will include these in a script to ensure the play is staged the way they want.

Sound cues

Read through the script twice, the first time to find out what happens, the second time to take notes of possible LX cues, small sketches of stage movements, sketch a simple lighting plan as a draft.

Bette & Joan

Garrick Theatre Production Season 1 13 to 29 February 2020

Bette Davis – Hollywood actress, 54. A star who has nothing to prove.
Joan Crawford – Hollywood star, admits to 54, although is 58; as an actress has much to prove.

Scene: The action of the play takes place in Hollywood during 1962.

A Note On Costumes includes Joan wears a hat. General Note: Colours should remain slightly muted to give the impression of grainy colourisation, as if of a black and white film that has been coloured. Some elements of the set could remain more black, white and grey.
We need to use soft pastel colours, perhaps a sepia effect simulating an old black and white film. Need to discuss with set designer and costume designer.

8:45 a.m. 
Time of day helps us choose colour, angles.”
(Lights up on a modest dressing room/trailer for Bette. A wheelchair for the character of Blanche, off centre. Dressing table, the mirror cut away, and chair centre stage, close to the adjoining wall of the other dressing room.)
(The overall visual effect is that of monochrome, as in a black and white movie, which has been colourised, giving a period and slightly muted effect.)
We could use Lee 156 Choco;ate for the cepia effect. Need to be done in consultaion with director and set designer. The cut away mirror may need working lights, to be discussed with director and set designer. Will need to see hot to get power to dressing table lights from dimmer.

Joan’s dressing room is similar. Mention of telephone ringing.
Telephone ringing can be done with sound effect or telephone ringer in Bio Box.

Later on in the scene Bette remembers a film scene from The Letter.
We cross fade to a night time scene in a rubber plantation. We can use gobos to simulate an outdoor scene.
The the lighting changes back to the dressing room.

At times the lighting could focus in on the actors when they are sitting at their dressing tables, facing each other, using longer fade times so that the audience is not aware of our shifting their focus.