Sakurako-sama
This is Kawaguchi Hidetoshi. This is my humble answer to the question.
The “nothing” described in the Heart Sutra is “denial of what is made up as an entity.”
We have a habit of being born with things and things as if they were, on the side of the thing itself, being held captive as if they were possible by something tangible that does not change forever and forever.
To put this habit in detail, it's called “Club Giving Up,” and Jikai-sama's explanation of the pot is really helpful.
However, it is the Heart Sutra that is explained as having no trace of dust (empty) that is actually established as such.
Well, when it comes to asking if there's nothing, that's not the case.
Actually, I and you both really exist right now.
There are various limitations, but of course there are things and things that have been recognized and captured.
However, although they do exist, their state is made up of how they are dependent on others (luck), and most simply, they can be due to various causal relationships (causes and conditions), and depending on that causal relationship, they change further. It does not exist as an entity, but changes in a way that depends on others is called “various acts are impermanent.”
Depending on the cause and cause, so does myself. The future will also depend on where I go, what I do, and the cause and effect of my work.
Both worldly happiness and enlightenment, which is the ultimate Buddhist happiness, depend on cause and effect. By reconciling good causes and relationships, we want to move towards good results.
Buddhism is also very useful for the sake of public happiness, and I would be grateful if you could continue with your studies.
Kawaguchi Hidetoshi Gassho