In your .profile (or .bashrc, .zshrc, etc):
Be sure to set GOROOT to /usr/pkg/gon where n is the version of golang that you
wish to use. Then add $GOROOT/bin to your PATH variable.
e.g., for go 1.20.4, add the following to the end of your .zshrc:
GOROOT=/usr/pkg/go120 PATH=$GOROOT/bin:$PATH