Orthanc for mac OS

i have installed orthanc in my imac(big sur) using the mac version. However, as comparison to windows version, there is no posgres.JSON inside the folder, only configuration.json is in the folder. Do i need to copy the JSON file from windows version?

The Windows configuration file is just a sample. To setup PostgreSQL, you can modify the “configuration.json” as described in the Orthanc Book:
https://book.orthanc-server.com/plugins/postgresql.html#usage

Just to clarify, i already created another postges.json file with the configuration as stated in the orthanc book. So, the correct way is to modify the “configuration.json”, instead of make another new json file?

You can indifferently use two configuration files (one for the main configuration, one for PostgreSQL), or use one single configuration file (that contains both the main options and PostgreSQL-related options). This is explained in the manpage of Orthanc, that can be found inside the Orthanc Book:
https://book.orthanc-server.com/users/man-orthanc.html

In the context of the macOS package provided by Osimis, if you use two different configuration files, you must modify the content of the file “startOrthanc.command” by replacing the line “./Orthanc configOSX.json” with something like “./Orthanc .” in order to read the configuration files from the working directory.