To install R-fields, run the following command in macOS terminal (Applications->Utilities->Terminal)
sudo port install R-fields
To see what files were installed by R-fields, run:
port contents R-fields
To later upgrade R-fields, run:
sudo port selfupdate && sudo port upgrade R-fields
Reporting an issue on MacPorts Trac
The MacPorts Project uses a system called Trac to file tickets to report bugs and enhancement requests.
Though anyone may search Trac for tickets, you must have a GitHub account in order to login to Trac to create tickets.