Just run this apt install command
sudo apt install pepperflashplugin-nonfree browser-plugin-freshplayer-pepperflash
After this restart your browser and check Adobe's site to verify if your Pepper flash is working and showing at least version 32.
https://helpx.adobe.com/flash-player.html
As you'll see below it will download the latest version which is currently 32 and this was not possible with the old/crappy deprecated adobe-flash plu........
Download the latest from Adobe's site and unzip it, enter the directory it creates and type the following:
sudo cp libflashlayer.so /usr/lib/adobe-flashplugin/
sudo cp -r usr/* /usr........
This is an easy fix and highlights a huge issue again with Linux and Flash still not playing nicely/working as well as Windows yet.
Solution - Go to "about:config" and disable the two entries (set them to false):
dom.ipc.plugins.enabled.libflashplayer.so
dom.ipc.plugins.enabled.libnptest.so........