Steps
First you would receive a call from the "gatekeeper" who informs you of a position that needs to be filled, say "high school science grade 10".
You arrive at the school and head into the office where you receive keys to the room, a lesson plan made by the teacher that is absent, a folder detailing school procedures & instructions. Then to the absent teachers mailbox to pick up any remaining materials. Any further information, such as handouts or reviews you will receive with written instructions once you reach the classroom.
Look into the folder given to you. It will usually include the following information: The emergency exit route in case of a fire or other problems, and any further information such as the absent teacher having to be a hall, playground or lunch monitor. Information on room number, as classrooms may change dependent on the day. Once finished, write any necessary information on the chalkboard.
Once students arrive engage in conversation. Let them know who you are, the duration of time you plan to stay, and the whereabouts of their teacher. Asking questions pertaining to how the absent teacher handles problems. Other than that, it is pretty basic as the students usually have a set guideline of work to be done laid out by the absent teacher.
If students misbehave, don't hesitate in being strict and forceful in your approach. Have them move from their seat to a less distracting area, confront their brash behavior in class. Do what it takes to keep the class in tact.
Once the students leave make sure the entire classroom is clean and organized. Homework given during class should be graded and left for the teacher. You then drop off your keys and other materials and head home.