Who is who in the Trump political trial?

The third political trial against a president in the history of the United States began on Tuesday. These are the characters that we cannot lose sight of now that the future of the presidency of Donald Trump is in the hands of the Senate. Here we resolve your doubts about what is the role of each person during the trial, who holds the reins, who sets the rules, who coordinates the president's defense with the White House, and who are the Democrats designated as prosecutors.