I was trying to watch HBO Go on a new Windows 10 laptop (brand new, I turned it on for the first time this morning.) HBO wouldn't play any video and said I needed to install Adobe, so I followed the link. On the Adobe page, it said that Adobe is integrated into Windows 10 and I did not need to install.
I checked that flash player is set to run in my Windows Edge settings, and I restarted as well. I also searched for Adobe on my computer and didn't find any programs under that name, but the website still says I don't need to install it.
Microsoft has STRICT controls on their Edge and Internet Explorers... you may NOT install or update Flash in those browsers
What you might be able to do is use a compatibility setting inside Edge for the HBO page
Search Microsoft – Official Home Page to learn how to manage Edge settings