Masking out some data for privachy


I cannot get ArcGIS Pro to make a connection to an Oracle database. The problem appears to be that I do not have the Oracle ODBC software installed with the "environment variable pointing to the installation of ArcGIS Pro."
I am sorry, but I have no idea whatsoever what it means to "point the environment variable to the installation" of other software. The documentation for the setup of this crucial environment variable provides no more hints on what that means.
This computer connects to the Oracle database thousands of times a day thoiugh oracle odbc.. Why can't ArcGIS connect once to the same database from the same computer?
What is this "pointing environment variable"?
What am I doing wrong, and how does it need to be done to work? This is a major point; I am so sick of this stupid problem that this company cannot find the English to make itself understandable.
It's not as if I am new to working with PCs or databases. I have been doing both for 40 years. The problem is you have constructed a unique way of talking about foundational components of computer systems, and you have made yourselves understandable.
My typing is a mess because I am so angry at the loss of hours on this stupid problem.