Second Instance Installation of PostgreSQL?
You don't need the binaries two times, you only need to create a second data directory (aka "cluster"). 

The following creates a new data directory under c:\ProgramData\pgdata2. I highly recommend to not put the data directory under c:\Program Files (that's one of the reasons I stopped using the EntpriseDB installer because it always suggested that)

"C:\Program Files\PostgreSQL\12\bin\initdb" -D "c:\ProgramData\pgdata2" 


Then edit c:\ProgramData\pgdata2\postgresql.conf and change the value for port, e.g. 

port = 5335


Then you can register the new Windows service and provide the data directory during registration:

pg_ctl register -N other-postgres -D "c:\ProgramData\pgdata2"


Once the service is registered, you can start it using net start

net start other-postgres