The Terminal application can be found in /Applications/Utilities The Terminal application can be found in Applications > Utilities > Terminal menu
The installer requires access to the internet to be able to download the FSL software appropriate for your platform and runs from within a terminal session, so you need to open a terminal:
Should you install as root see the configuring your account for FSL section for details on how to use the installer to setup your user account for FSL. If you don't have permission to use sudo (an administration account on macOS) then the installer will fail and will need to either install into a folder belonging to your user or to run the installer as the root user. If this is the case, the installer will attempt to gain these privileges through the use of the sudo command, which will require you to enter your password for verification. the default, /usr/local) may require administrative privileges. Installation into certain folders on your computer (e.g. Administrative privileges may be required
