Can you share more about using the breath as a focus? Is it breathe in from nose and exhale from mouth?
There are many forms of meditation and the method that I use is called single-pointedness meditation.
The goal of meditation is the cessation of mental noise that arises as random thoughts. These thoughts may have roots in worry, fear, anxiety, or other emotions (even what we may conventionally term positive thoughts). These random thoughts are distractions and impact our ability to focus on the present-moment i.e. what we are working on. They impair many aspects of our life e.g. performance, focus, concentration, etc.
Cessation of all random thoughts is not trivial so we set a lower bar first by focusing our mind on a single point. There would be an object of focus and that can be external or internal.
External examples include the tip of our nose, a candle flame, the ring of a bell, anything external that we can perceive.
Internal examples include a single thought, our breath, our heartbeat, anything internal that we can perceive.
I use my breath (in, out, in, out at a regular unforced interval) as the object of focus in my meditative practice.
With sufficient practice, this becomes subconscious, and there is no longer a need for a specific session. Meditation becomes simultaneous with daily activities. The key is having sufficient practice to the point where it becomes subconscious (just like learning how to ride a bicycle).
Once meditation becomes subconscious, then the object of focus (breathing in my case) can be used to "reset" the mind at any point in time.