Adding the UWP Community Toolkit to your Visual Studio Toolbox
Add the UWP Community Toolkit controls into the Visual Studio toolbox by following these steps:
1) Add the Microsoft.Toolkit.Uwp.UI.Controls NuGet package to your application.
2) Open any XAML page and select the Toolbox on the left side of Visual Studio.
3) Right click in a blank area and select Add Tab. Name the tab UWP Community Toolkit Controls.
4) Right click in the tab you just created and select Choose Items.... Then select Browse from the Choose Toolbox Items dialog and navigate to the folder on your machine:
a. Choose the folder name matching the version you have installed, then continue to the lib\uap10.0 folder and select the Microsoft.Toolkit.Uwp.UI.Controls.dll file. You should end up with a dialog similar to the one shown below.
5) Your toolbox should now have a list of UI Controls from the toolkit that you can drag and drop onto your XAML surfaces.