As an A.S.M. (Assistant Stage Manager) you are expected to undertake a variety of different duties as part of your job. These can range from working on The Book, which involves being in rehearsal from the first read-through, being in the rehearsal room and making notes of all the moves the actors make during the blocking during the early stages of the rehearsal of the play, right through until the show goes onto the stage, giving cues from the prompt copy, for sound, lighting, spot effects (ie door slams, glass crashes, flying, etc etc.) You might be expected to run the props for a play, being in rehearsal and 'plotting' props (properties) for the whole show, making sure that they are set in the correct place on set and off and that the actors get their 'personal' props (smaller items that they carry on themselves, from umbrellas, glasses, books, handbags etc. as well as things like letters, money and so on inside wallets, pockets etc.) This plotting is essential because most, if not all, props are vital to the play in some way or another. For example, if the play is a thriller or 'who-dunnit', where there is a murder, some of the props might be clues for a policeman to discover such as a revolver or knife and if it is set in the wrong place it might ruin the story of the play in question. During the rehearsal period sometimes these props can be moved to a different place on the set (or even off) and it is important for the person on 'props' to note exactly where these changes are made.
Sometimes you can expect to do some really odd things which might otherwise not be seen by the audience but which will have quite an important part to play in the over-all production. One such thing I recall was on a production of a play called "Busman's Honeymoon" at Liverpool Playhouse. It is an adaptation of one of Dorothy L. Sayers 'Lord Peter Wimsey' novels. During the course of the action Lord Peter (Played by an actor called Neil Cunningham) uncovers a vital clue which leads to the discovery of how the murder was done and which is the central to the whole play. One of the characters is murdered by the fact that he/she is knocked unconscious (I'm not certain now if they weren't supposed to be killed, which I imagine they would be as the whole play revolves around a murder.) by a swinging flower-urn which is suspended from the ceiling of the set. For some unfathomable reason Lord Peter decides that the clue to this is hidden up the chimney of the cottage in which the play is set. He decides for some reason best known to himself that he will fire a rifle up the chimney to dislodge the item which is supposed to be hidden up there. (Are you with me? I hope so, as this is quite complicated to explain.) To achieve the desired effect of soot and the object (which was a chain or something, if memory serves we correctly.) it was necessary for myself to be standing off-stage on a ladder above the mocked-up stage fire-place. Actually rather precarious, not just because I had to balance on the ladder, but to also be responsible for a real weapon. (What would health and safety have to say about THAT I wonder ?) At the correct point in the play I was given a cue and had to fire off the hand-gun to simulate the rifle being fired by the actor playing Lord Peter Wimsey and at the same time tip the chain and mocked-up soot down the chimney (actually sawdust which had been dyed black.) Thinking about it now it must have looked really odd to anyone watching, someone standing on a ladder with a pistol, firing it off as a prop rifle appears through the stage fireplace and then throwing down pretend soot. The things one does for one's art!