Notice the use of the terms "right" and "center," which along with "left" are theatrical shorthand for Stage Right, Stage Left and Center Stage. Right and left always refer to the actors' right and left, and center is the center of the stage. Sometimes you'll also see "upstage" or "downstage," or their shorter forms, *up and *down. The latter terms get their names from the early days of theatre, when stages were raked, and if you walked toward the back of the stage, you literally walked up, and if you walked toward the audience, you were walking down. Few raked stages exist, but we still use the terms.
Character Name Element
Characters' names may appear in two ways: before dialogue and contained in the stage directions. Character names that precede dialogue are always capitalized aligned at a 2.5" tab stop. In stageplays, opposed to screenplays, you are permitted to use boldface to further set the character name apart.
PERRY They were your dogs. And Rover just ran away. We don't even know for sure he's dead. MARLA It's been two years. PERRY Probably found an owner who fed him more than Diet Dog.
For character names that appear in the stage directions you have the choice of two formats. The first format is like screenwriting: the character name is in all CAPS the first time it is introduced in the stage directions, after that it's always in mixed case. For example, I introduce Marla in this At Rise description.
(Late afternoon. A living room. MARLA, thirty something, holds a cardboard dog and looks out a window, which might be indicated by a hanging frame.)
But later in the play, I write
(Marla strokes the cardboard dog.)
The second way to format character names in stage directions is to use ALL CAPS throughout. It's a matter of personal preference: pick the format that seems most readable and stick with it.