Yeah, theres not really a carved in stone specific method for tending the stove. You'll find your variation of stove operation thru just doing it.
Fly ash is basically ash dust that is very light and will follow the air currents. Shaking with the ash door closed will make for less of it going up and settling in the pipe.
But since you are a new coal burner, doing the whole tending procedure every 12 hours will give you good learning experiences even if the stove doesn't absolutely need it. Maybe in a few weeks you can try extending that time between tendings, or possibly doing a half version for morning then a full version at evening.
When I ran my hand fed stove I did 24 hour burn cycles mainly. Only thru extremely cold days would i do 12 hours, usually 15-20 days per year. Then on really warm days running low and slow I would skip days, doing 48 hour burns..
The first season is about learning what your stove needs to keep it happy and developing a routine that works for you