To u/Anxious_Solution_282 as well:
You can either read the FAQ question 3, use Flashpoint, or go to a website that's using an emulator (e.g Kongregate is using Supernova and Newgrounds made their own).
go here: https://bluemaxima.org/flashpoint/downloads/
download the latest infinity version, NOT THE ULTIMATE, right now is the Flashpoint 10.1 Infinity
if you need any further help with the instalation you can ask for help in their discord server (last link in the page) or just mention me here again
My time to shine! You don't need Steam - try Bluemaxima's Flashpoint. It's a project which aims to store as many Flash games as possible so that they can still be played even after Flash has been phased out. All 3 SFH games are in the latest build. Here's the list of games: