how to use android-support-v7-appcompat - XoilacTV

It's easy to get started with the Support v7 AppCompat library by simply installing the NuGet through the NuGet package manager in Visual Studio or Xamarin Studio. After you have the latest NuGet packages installed, you will want to ensure that you properly configure your theme by following this guide. Introducing AppCompatActivity.

v7 appcompat library Part of Android Jetpack. Note: The appcompat library has migrated into the AndroidX library, which is an Android Jetpack component. See it in use in the Sunflower demo app.

Android AppCompat Library V7. ». 28.0.0. The Support Library is a static library that you can add to your Android application in order to use APIs that are either not available for older platform versions or utility APIs that aren't a part of the framework APIs. Compatible on devices running API 14 or later.

It says I should use SDK manager to download and add v7-appcompat, however I have to connect to internet through proxy and when I use SDK manager it cannot download anything. So how can I download and add v7-appcompat?