Setting it up is fairly simple: you obviously need to have autofs(5) enabled in /etc/rc.conf:
autofs_enable="YES"
And you need to have the autofs(5) daemons running - just like other deamons in FreeBSD those will get started at system bootup if autofs_enable was set; otherwise you need to start them by hand:
# /etc/rc.d/automount start # /etc/rc.d/automountd start # /etc/rc.d/autounmountd start
FreeBSD From the Trenches: Using autofs(5) to Mount Removable Media