What does "nose breath" mean?

"You should not try to find the point where the moving air strokes the nostrils, but keep your focus at the nose breath".

This means to not try to feel, track or be aware of the breath sensations. Instead, it means to only keep the mind exclusively focused towards the nose. It means to never concern yourself with watching the breath, even if the breath comes into the mind as an object of awareness. Just keep the mind still & anchored in one place.

As already mentioned in this answer, you can start by looking if:

Breathing in long, he knows that he is breathing in long.

Breathing out long, he knows that he is breathing out long.

Breathing in short, he knows that he is breathing in short.

Breathing out short, he knows that he is breathing out short.

Always mindful, he breathes in; mindful, he breathes out.

If you already have not taken a retreat perhaps you can try one.

Also following book might be a additional references:

• ANAPANASATI - MINDFULNESS WITH BREATHING Unveiling the Secrets of Life: a Manual for Serious Beginners by BUDDHADASA BHIKKHU
• Ānâpāna,sati Sutta
• Mahā Sati’patthāna Sutta

It looks like you have found the right article on how to practice the Breathing Meditation. Than rejecting this, instead try to concentrate on training the mind. All the Buddha’s teachings— on generosity, virtue, and meditation, or on virtue, concentration, and discernment—are aimed at training the mind because the mind is what shapes our experience of pleasure and pain, happiness and suffering. A well‐trained mind can deal with issues that you come across in meditation. This require effort. They go against the grain. You have to learn not to let your resistance to the effort get in the way. You need a clear sense of cause and effect. That’s what discernment is all about: seeing what really works in terms of cause and effect, what doesn’t really work, and then adjusting your actions accordingly. We’re here to train the mind to be its own best friend.

One way of doing this is to focus on your breath. It is best if you’ll sense the breath as the feeling of the air moving in and out of the nose, but if it is difficult, then be aware (but not solely focus on) the rise and fall of the abdomen, the rise and fall of the chest. Sometimes can sense even in your arms or your legs whether you’re breathing in or breathing out. Allow breath to come in as long as is comfortable, and then allow yourself to breathe out as long as is comfortable. Try to sensitize yourself to what feels good right now in terms of the breathing. Think of yourself as hovering around the breath. You’re not squeezing it out; you’re not forcing it in; you’re just staying very close to it, watching it, letting it adjust in whatever way feels good, giving it space to adjust. The more satisfying the breath is, the easier you will find it to stay with the breathing. If the mind wanders off, just bring it right back to the breath. If it wanders off again, bring it back again.

Mind will want to wander around. That’s what the mind is used to doing. But if you’re firm with it, and if you can master just this one skill, you change the way you relate to your body, you change the way you relate to the present moment, you have a greater reserve of wellbeing to draw on in any situation. Do not be too grim about the meditation. Find pleasure in, and be happy even if it a short while that you were with the breath. It takes time, it takes training, it takes discipline. But you must remain happy to do it well.

In this guide, Thanissaro Bhikkhu wrote:

Only when you have cleared the mind in this way, and set outside matters aside, are you ready to focus on the breath. Bring your attention to the sensation of breathing. Breathe in long and out long for a couple of times, focusing on any spot in the body where the breathing is easy to notice, and your mind feels comfortable focusing. This could be at the nose, at the chest, at the abdomen, or any spot at all. Stay with that spot, noticing how it feels as you breathe in and out. Don't force the breath, or bear down too heavily with your focus. Let the breath flow naturally, and simply keep track of how it feels. Savor it, as if it were an exquisite sensation you wanted to prolong. If your mind wanders off, simply bring it back. Don't get discouraged. If it wanders 100 times, bring it back 100 times. Show it that you mean business, and eventually it will listen to you.

Here, he says "don't bear down too heavily with your focus". That means, that goal of this exercise is not to investigate how the movement of air is working on the nostril. Rather, the goal of the exercise is to focus or latch the mind onto something it can concentrate on, and keep it from wandering.