Various sciences are engaged in the study of the mechanisms of the subconscious: psychology, physiology, philosophy, medicine.
They study the principles and mechanisms of the subconscious mind in books on hypnosis and psychotherapy
These issues are dealt with by academic experimental psychology. Those. psychology as a science, not a spoken genre.
To learn more about this concept, it is highly desirable:
-1- fluency English
-2- have access to scientific psychological journals. For example, there are many scientific journals on the APA (American Psychological Association) registry. I draw your attention to the fact that you should not be guided by Russian journals.
-3- understand how science differs from pseudoscience (psychoanalysis, etc.)
And then look for articles titled "unconscious mind ".
Well, you also find real scientific data, not speculative opinions.
Since the time of grandfather Sigmund, oh, how much water has flowed under the bridge!
If you are interested in the mechanisms of the subconscious, then they are engaged in the new science of intellectology. It examines the activity of the subconscious in terms of what information is processed and how it is processed, how it differs from consciousness and reason.
A detailed answer to the question would turn into a whole lecture. If you are seriously interested in this, I will tell you on Skype - geena_rolf.
So psychology. And you can start with Freud. In the modern world, when they talk about the subconscious, most often they mean the work of the defense mechanisms of the psyche:
1) Displacement of difficult memories (from consciousness to subconsciousness)
2) Introjection of beliefs (" you have to be good "," you can't stick your fingers in the socket ")
3) Projection (" he pisses me off with his arrogance, I don't allow myself to behave so impudently ")