This suggestion is not based on an assumption that you don’t know how to count up to ten unaided! This is a useful technique that I’ve used when my mind has been very distracted and I need a bit of a hand to get it under control.
What I do is very simple; in the first two stages I count on my fingers as my breath flows in and out. I don’t move my fingers but simply take my awareness into each finger in turn, starting with the thumb of my right hand, working my way through the fingers of that hand in turn, and then continuing from the thumb to the pinkie on my left hand.
This really does help to keep your mind more firmly anchored than when you simply follow the breath alone. So why not use this all the time? Well, you could, I suppose, but I find this technique mainly to be of use when I’m very distracted. Once I’ve managed to get my mind to settle down I let go of it.
The reason I do this is because I find that counting on my fingers is effective but slightly crude as well. I think that if you relied too much on this method it would stop you from developing more refinement in your practice. Perhaps it would be like never getting beyond using stabilizers (training wheels) when learning to ride a bicycle.
Although I said that I don’t move my fingers, I felt that I actually had to do so when I first tried out this method. Unless I physically moved my fingers a tiny bit I found I had difficulty telling which finger was which (and that’s despite spending years trying to learn the trumpet).
Perhaps you won’t have the same problem and can go straight onto counting your fingers without having to wiggle them. I stress that I don’t do this all the time – I only use this method when my mind is particularly unruly and needs to be, well, taken in hand.