Disciplining the mind means not allowing your thoughts to control you, to succumb to them or allow them to overpower you.
You recognise that thoughts in themselves have no power over you; it is you who has in the past empowered them with your imposition of happiness or unhappiness. It is you who has given your thoughts the power to prosecute you. In Sanskrit this is called jiva sristi.
Disciplining the mind means to stand by your decisions. Disciplining the mind does not mean removing all your thoughts; it means you do not allow any thoughts to control you any more.
If you wish to sit down in silence then you so, when a thought arises I want a cup of coffee, or I must go and hang out the washing you remain sitting in silence, not allowing your thoughts to control or dictate to you.
Perhaps you might like to make an intention, every time your phone rings, rather than reacting straight away, pause catch your thoughts, catch your breath and then consciously choose to pick up the phone.
Each time you do this you break the chain of constant thoughts and literally ‘have a breather’, a break from the constant activity in the mind.
It is easier to master this discipline with objects first as they do not react, humans do.