The way I was told to remember the correct stair order is the "bad" lef, foot, ankle, or knee stays down in hell while the good leg goes up to heaven.

I stayed overnight at the hospital after my TKR and the next day the PT had me going up and down stairs one step at a time. It was not a problem after that though I did camp out on the living room sofa for 2 or 3 weeks just in case some emergency arose and I had to get out of the house quickly.

Good luck.