idiot needs help

Apologies if this is the wrong place to post, I’m new to Kodi and not especially technical…I’ve downloaded kodi onto my PC (windows 8), version 17.1, and I’ve been recommended a couple of builds and I think (hope) I follow the instructions correctly to install. I get to the point where Kodi asks me if I want to force close which I agree to but when I restart Kodi I was expecting the look to have changed dramatically but it’s exactly the same – apart from in the add on part it has the build I installed but if I click it then it just seems to give me the option to reinstall.

Help pls