Stairs and Crutches
Use one crutch and the stair rail if present (only if the railing is stable and there is someone to carry the other crutch). Use two crutches if there is no stair rail.
It does not matter which side the stair rail is on.
If both crutches can be held in one hand safely, you can use both crutches on one side and the railing on the other.