can't install flashplayer on my windows10 preview phone

To Whom it may Concern; I have a Nokia,Lumia 640 Windows Phone. It's original O.S. was Windows 8.1 Update 2. Currently it's been updated with a Preview version of Windows 10, which is to be released on July 29th, 2016. When I attempted to run a network speed test , through my provider,they informed me that my Phone needs to have Adobe Flashplayer installed, which I've not been able to do. I would greatly appreciate any assistance to this matter. Thank you!