Your soul, like a soldier on watch observes all the movements of the heart, everything that occurs inside: thoughts, impressions, judgments, intentions, inclinations, passions, desires, distractions, etc., summed up, all your internal and external acts, thoughts, and words.
This vigilance requires a certain recollection and can’t take place in a dissipated, self-indulgent, or distracted soul. Think about a butterfly that flutters from here to there, sometimes they look like they can’t make up their mind what direction to go. They’re all over the place! Our hearts can be like that… sometimes we’re just all over the place, like a chicken with its head cut off… or a squirrel with its head cut off (if you have experience with squirrels)!
But don’t think because you are a person that is very easily distracted you can never have a recollected soul. That’s the whole point of keeping watch over your heart, to fix that headless chicken syndrome. Keeping vigilance over your heart will make sure that those distractions become less and less. With practice you will become more accustomed to keeping watch over your heart and with time it will become easier.