You do not need to install Flash Player.
Steps to troubleshoot Flash Player on Windows 8
Enable Flash Player
Disable ActiveX Filtering
Update Internet Explorer to get latest version of Flash Player
The content can require a later version of Flash Player than the one you have installed. See if you have installed the latest Flash Player version by visiting the Find Version document. The second step in the document displays the version of Flash Player that you have.
Flash Player is embedded in Internet Explorer in Windows Store and Desktop Mode. You can also download and install the latest update from the following links:
If you are a Windows RT (tablet) user, you can get the updates only through the Windows Update mechanism.