The bell just rang, the class is looking at you, and the teacher who normally runs this room is not here.
The written walkthrough below is complete and current — it is the same steps the video will show.
"Hi, I'm your substitute today — your teacher is out, here is what we're doing." A short, confident script like this settles a room faster than silence does.
Walk the room rather than sitting at the desk. A student who is drifting is easiest to redirect early and quietly.
Walking over to a student who needs redirecting keeps the room calmer than raising your voice across it. A seat change is a normal, low-drama response to repeated disruption.
Most schools use one hall pass per gender, and water usually does not need a pass. If a student who left on a pass is not back in about 30 minutes, send another student to check on them, then call the main office — do not leave the rest of the class unattended to go look yourself.
In elementary school (and sometimes middle school) the substitute walks the class to lunch, specials or an assembly. If nobody has told you the routine, ask the main office or the students — they usually know.
Take the class to the designated dismissal spot, wait at the door, and hand off each child only to a parent who signs for them. Any child who is not picked up goes to the main office — never send a child off on their own because the day is ending.
Check the room is in order, sign out if your school requires it, return any keys or materials, and leave a short note for the returning teacher about what was covered and anything they should know.