What are you doing right now?
Is it one thing? Or is it a number of things?
How many different thoughts and actions are occupying your mind? What about your unconscious mind?
When was the last time you focussed on just one thing? When did you last really get lost in something to the point where everything else seemed to disappear?
How long did that last for? How long before you allowed another thought to wander in?
We’re only really capable of doing one thing at once.
Accept that. Allow everything else to pass you by.
Find your single task and let your mind become enthralled.