Unable to install extensions in Safari
I have OS X Yosemite 10.10.5 and Safari 9.0. When visiting the Safari Extensions Gallery there are no "Install now" links.
My thinking was I might have to upgrade to El Capitan to be able to install extensions, but I see others who have already upgraded are having the same issue. I'm a new Macbook user.. not the way I wanted things to start. I have tried to watch the tours of both Yosemite and El Capitan but the "Install now" links are still missing. I have tried going through Safari > Safari Extensions... and Safari > Preferences... > Extensions > Get Extensions and both fail to show the links to install. I have also tried repairing permissions. Any help to fix this issue would be greatly appreciated. Thank you.
MacBook Pro (Retina, 13-inch,Early 2015), OS X Yosemite (10.10.5)