In a Windows terminal, you can use Strawberry Perl to run Perl scripts. However, there are additional details needed for working in a Windows environment, and those are not covered here.
A simple way to get a Linux terminal is to install Ubuntu 18.04 for Windows 10.
Many of the instructions on this site assume you have a Linux terminal. Windows Subsystem for Linux (WSL) is one way to get that on a Windows machine. The preferred Linux system is Ubuntu, currently 18.04. The purpose for setting up a Linux terminal is that DLS has created some Perl scripts to do things (like add, delete, rename or rearrange fields, etc.) to the SFM files in order to make the file easier to import correctly into FLEx. These scripts can only be run in a Linux terminal.
It is beyond the scope of this material to explain how to use WSL, but the most important things you need to know are:
How to start it and get a terminal window
How to find a Windows folder/directory from the terminal
How to change directories within your Windows directory structure
How to run Perl