Use (“V”) to show all the patients status on screen. You will have special triage bandages (add them to your action bar/hot key) which should be applied to Critically injured, then Badly injured, and then injured. Once you started treating a patient do not interupt, just finish treating that patient before moving on to another patient. You should select your next patient before your are finished with the first one, then all you have to do is hit you hot key to start the next one.
This Shadow Talent Build is the fastest for Leveling Up a Priest Class from 1-60 in WoW Classic patch 1.12. Spamming Shadow Damage DOTs while kite mobs will be the name of the game with this build, having the ability to sustain your health is just a bonus. You will just need to make sure you are stacking enough spirit so you don’t run out of mana often as that will slow down the levelling process drastically.