The english word "suffering" for the term "Dukkha" does not do it much justice. The Buddha said ( Source: https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca1/dukkha.html)
"Birth is dukkha, aging is dukkha, death is dukkha; sorrow, lamentation, pain, grief, & despair are dukkha; association with the unbeloved is dukkha; separation from the loved is dukkha; not getting what is wanted is dukkha. In short, the five clinging-aggregates are dukkha."
— SN 56.11
This sums up everything that is Dukkha.
Now while meditating how do we realise Dukkha. First of all in Vipassana Meditation, we never do it with music as it is a distraction. So , please do not do that. Meditation is done with the aim of seeing "reality" as it is by transcending our faulty perceptions and societal conditioning.
How do you know Impermanence while Meditating?
For example : You are meditating for half and hour and you notice an itch in your knee. You do not scratch but only observe it. While observing it you notice that after a while it ends , and some other sensation begins somewhere in your body. This is showing you the impermanence of sensations.
How do you know non-self Annata and Dukkha?
With more practise in meditation and realising the impermanence of things around you , you will realise this as well. However , it takes practise.
In order to understand these things , I suggest you practise more for yourself and try to understand these concepts at an experiential level , through your own experiences. Merely intellectualizing these concepts will help only a little.