If a fully fitted stair carpet is required always leave the planning and laying to an experienced carpet layer.
When laying strip carpet, which is easier to lay and costs less than a fitted carpet, always lay the pile facing down the stairs to ensure longer wear. If the tread feels smoother to the touch when rubbed towards the nose of the stair. It is facing the correct way.
For the neatest and safest finish use tackless fitting strips to secure the carpet. Either use right-angled tackless fittings or. For a very secure fixing, two separate fittings for each stair.