.Net Standard

Hello Everyone,

I want to change for .Net Standard so i tried this :

https://oren.codes/2017/04/23/using-xamarin-forms-with-net-standard-vs-2017-edition/

But i have problem with PackageReference is not recognized.

I think it's because i didn't make step 1 but i don't understand what i have to do, any one can explain more? For me i have to uninstall all package, Am i right?

Any one have a video for do that ?

Thanks in advance.