I personally prefer to learn it from the front. I only teach the very first phase and tell the group to expect to wipe after the transition.

If there are key enemies to shoot or whatever I will send a screenshot into discord because the game has no good way to mark targets besides shooting them.

The main reason I like this method is because trying to do the whole fight in one go is just too much to infodump on someone. By the time they are ready for the phase 2 info, they will have enough confidence in the p1 strategy that you dont have to worry about pushing any knowledge out of their active memory.

I was also the raid leader for my WoW guild so the method does scale. You do need people who are able to learn from their mistakes though... Some just never figure out to move out of the fire.