If you want to use Flash in a browser or an app, follow these instructions.
Browser Installation
If there is Flash Player already installed, use the Uninstaller for Windows, otherwise use the Uninstaller for Mac OS X - 10.6 or higher, or the Uninstaller for Mac OS X - 10.4 & 10.5.
After that, run an installer from the table of installers depending on your device with the version you want. The versions suffixed with “pep” are PPAPI (WebKit and Blink), the ones with “ax” are ActiveX (Trident and EdgeHTML) and the ones without suffix are NPAPI (Gecko and Goanna). Follow the instructions on the installer that you chose. Reminder that most major browsers such as Google Chrome, FireFox, and many more, will no longer accept any flash version.
Next, find a browser that allows Flash plug-ins, you can visit this page to find some.
App/SWF Installation
In the "SWF Installation", an already installed app is waiting for you. However, you'll need a SWF file (Shockwave Flash) to run. I left a SWF game here for you to try out.
If you need to change your global settings, visit this site.