In William Styron's Darkness Visible, what relationships seem to be supportive or unsupportive for the people involved? How do those relationships play out as they deal with their mental health challenges? How is symbol or metaphor operating in the work? What do those symbols or metaphors seem to mean for the people involved, and what meaning do they hold for us as readers? What meaning or power do voices have in the work? These voices could be present in consensus reality or only heard by the person or character, and they may be implied, suggested, or hinted.

Let's start by breaking down each question into parts that you might find easier to understand.
What relationships seem to be supportive or unsupportive for the characters or actual people involved?
This question asks you to focus on the relationships between the characters in the work. First, identify the characters and then think about how they connect to one another; are they friends, or lovers, or relatives, or work colleagues, for example? Once you know what kind of relationship you're dealing with, you can decide if you think the relationship is supportive for one of the characters involved or unsupportive.
How do those relationships play out as these personages deal with their mental health challenges?
This question asks you to look at the impact of a character's mental health issues on their relationships. For example, can the friendship survive the pressure, or does it crumble when things get tough? Is a marriage strengthened by challenge or weakened by it? Does someone get fired because their work relationships cannot handle the mental health issues?
How is symbol or metaphor operating in the work or works? What do those symbols or metaphors seem to mean for the characters (or real people), and what meaning do they hold for us as readers?
These questions are complicated because they are asking you to analyze the work within the context of two complex literary terms: the symbol and the metaphor. Both symbols and metaphors are used by writers to represent something else meaningful; for example, a pattern of sunny days may symbolize optimism, while descriptions of nighttime may be a metaphor for inner darkness. These questions ask you to discuss the writer's use of these kinds of literary terms throughout the work, so it would best to start by finding examples of symbols and metaphors in the text that make sense to you.
What meaning or power do voices have in the work or works? These voices could be present in consensus reality or only heard by the person or character, and they may be implied, suggested, or hinted at.
These questions ask you to concentrate on voices. Locate descriptions of voices and important moments in the work when voices play a big part before tackling the second part of the question. Decide for yourself why voices are important enough to be mentioned in this question. The second part of the question simply lists examples of voices that might make for an interesting discussion.
Hope this helps! Good luck.

Darkness Visible is William Styron's memoir of his descent into, and eventual recovery from, depression. The book was one of the first to address depression in such a frank and personal manner, and is still considered one of the best on the topic.
Now, let's dive into your questions:
What relationships seem to be supportive or unsupportive for the characters or actual people involved? How do those relationships play out as these personages deal with their mental health challenges?
A memoir, Darkness Visible is told from the perspective of Styron, a novelist who received countless awards over the course of his career, including for his novel Sophie's Choice.
The two most important relationships Stryon discusses in the book are those with his wife, Rose Burgunder Styron, and his doctor, Dr. Gold.
Although Dr. Gold is a Yale-educated psychiatrist, he proves to be cold, aloof, and largely unsupportive of Styron. Gold is uninterested in the details of Styron's illness and mostly repeats information straight from the Diagnostic and Statistical Manual of Mental Disorders, a psychiatry text. He prescribes Styron a series of ineffective medications and fails to admit him to the hospital, despite the seriousness of Styron's condition. (There was a great deal of stigma surrounding mental health treatment at the time.)
On the other hand, Styron's wife Rose is incredibly supportive of her husband, providing him with the emotional support he needs to check himself into the hospital (where he ultimately recovers), despite the advice of Dr. Gold.
How is symbol or metaphor operating in the work or works? What do those symbols or metaphors seem to mean for the characters (or real people), and what meaning do they hold for us as readers?
As a writer, literature and the arts hold powerful symbolic and metaphorical value for Styron. The book begins with Styron's trip to Paris to receive a prestigious literary award. It is there that Styron's depression first descends. The prize symbolizes the power of Styron's depression—despite his successful career and incredible good fortune, he is unable to enjoy his life, experiencing extreme sadness, hopelessness and suicidal thoughts.
Conversely, it is a piece of music—Brahms' Alto Rhapsody—that helps lift Styron's depression, making him realize he doesn't want to die. The music symbolizes the beauty and wonder of life, and reminds Styron that he has much to live for.
The book is also filled with the names of other renowned artists and thinkers, such as Albert Camus and Primo Levi, who Styron says suffered from depression. These artists represent strength and support for Styron, making him feel less alone, and inspiring him to fight his way back into life so that he can create and thrive as they did.
These symbols hold much the same meaning for us as readers. Styron's misery despite his professional triumph shows the crushing agony of depression; his love of Brahms provides an example of life's gifts, and offers a beacon of hope to others suffering from the disease.
What meaning or power do voices have in the work or works? These voices could be present in consensus reality or only heard by the person or character, and they may be implied, suggested, or hinted at.
The voice of Dr. Gold indicates the resistance and difficulty many face in getting help for their depression, while Rose's voice shows the power love and support can have in helping the sick overcome their illness.
The most important voice in the book by far, however, is Styron's own. He provides the reader with an articulate, informative, and personal view of depression, a disease that is notoriously difficult to explain and understand.
With his book, Styron hoped to lift the veil on this little-understood disease, and shine some light on the darkness of depression.