Jaja asks about how "broad" the meditation object - the point of focus - should be; and he mentions the issue of maintaining stillness. I would like to step back to consider these questions by beginning with the issue of what we call "distraction."
At a fundamental level it does not matter how wide or narrow the meditation object is, or whether we are moving or still. The only thing that matters is the quality of our engagement with the meditation object. Let's start at the basics. Meditation deals with awareness. We are already aware; we don't have to do anything to be aware, because we are already aware. And, if we are aware, we are aware of something. In other words, awareness always has an object. If I am seeing, I am seeing something. If I am thinking, I am thinking something. In the context of meditation, we call this "something" the meditation object.
Notice that if I choose to meditate on a specific object - let's say, breathing - then I am not just working with awareness itself, but attention. Attention chooses some aspect of the field of awareness and focuses on it. This act entails some degree of effort, and it necessarily introduces distraction. After all, I choose to be aware of breathing, but find myself lost in thinking - I am "distracted." Distraction is bad, from the perspective of attention - I am not focusing my awareness on my chosen object - but neutral from the perspective of awareness - I am aware, but at this point it is the distraction that I am aware of. So it is important, for me, not to get caught up in concerns about distraction. Distraction is inevitable, unless one's attention and concentration are perfect. Which they are not. Let's say I decide to focus for 30 minutes on my breathing. Can I? Some people can, but most cannot. For most, this is an impossible job. But this does not matter. What we all of us can do is be aware, now. Right now, what am I aware of? This is the central question, pointing to the central activity: now, aware of what? Forgetting what happened before, or what may happen later - because both these are just thoughts arising now.
When we approach meditation from this angle, then although we may make certain craft decisions, like whether my meditation object should be wide or narrow, or whether it is permissible to move or not to move, once we begin to practise these are not the central issue. The central issue is: What's happening, now? The rest will take care of itself over time.