This is my order of operations. Learned it in high school welding too. Harris has a page with the same sort of info
How to Properly Light, Adjust and Shut Down an Oxy
Start the job with materials and tools ready, and safety inspection of all hoses and fittings
ensure torche valves are closed
turn on tanks
adjust regulators if needed
open o2 torch valve to purge lines, then close
open acetylene torch valve to purge lines
reduce acetylene torch valve to 1/2, light torch and increase flow until flame leaves tip, then back off until flame is at tip again
open oxygen valve until flame is neutral
readjust regulators if needed
adjust torch valves until flame is as desired, reducing, neutral, or oxidizing.
ready to work
Shut down
turn off oxygen torch valve first- this avoids detonation inside torch
turn off acetylene torch valve
close tank valves
open o2 torch valve to purge pressure, close torch valve
open acetylene torch valve to purge pressure, close torch valve
regulator should not show pressure on tank or regulated dials
back out regulator screws if unit will not be used again soon.