Help with my MacOS PostgreSQL 12 installation

This is my first post so if I’m in the wrong place please help me get to the correct list.

Issue:

I installed PostgreSQL on my Mac over a year ago and since upgraded my disk drive and OS to Big Sur. I am a retired Software Engineer and still like to program and am learning PostgreSQL and have it working on Linux and FreeBSD. In any case I had put it on my Mac laptop and want to use it again but it seems that the upgrades I did might have rearranged file locations or they may have been lost. I have been trying to understand what is where and come to a point where I need help getting PostgreSQL running again. I have a file with notes on the installation and here it is:

Installation Directory: /Library/PostgreSQL/12
Server Installation Directory: /Library/PostgreSQL/12
Data Directory: /Library/PostgreSQL/12/data
Database Port: 5432
Database Superuser: postgres
Operating System Account: postgres
Database Service: postgresql-12
Command Line Tools Installation Directory: /Library/PostgreSQL/12
pgAdmin4 Installation Directory: /Library/PostgreSQL/12/pgAdmin 4
Stack Builder Installation Directory: /Library/PostgreSQL/12

1. PostgreSQL server is not started and I am having trouble figuring out how to start it because /Library/PostgreSQL/12 does not exist. (don’t know why)
2. The password for user postgres does not work. (I can fix that but have not yet)
3. Don’t remember how I installed PostgreSQL but looks like with EnterpriseDB because of the installation directory. (I got this from postgresapp.com <http://postgresapp.com/>)
4. I looked around the postgres user account directory and it appears that PostgreSQL is installed there which confuses me because I can’t find any information about that or how to start or access it in that manner.
5. Looking for advice on how to unravel this situation and get my install up and running. I do have 1 database associated with some Java Web Development in this implementation.

My macOS is at Big Sur 11.5.2

Would appreciate your kind help.