Method 1:

Click on the Block content ribbon button under the Add-ins tab in Autodesk® AutoCAD®.

The block library palette will show up.

Select the Block to insert the drawing.

Double-click on each block preview in the palette to find the available blocks with different sizes. 

Method 2:

Open the drawings that have the block directly at: C:\ProgramData\Autodesk\ApplicationPlugins\3DPipingBlocks.bundle\Contents\Libraries.

The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin.

You may need to restart the Autodesk product to activate the app/plug-in.

To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 7/8.1/10/11) and uninstall as you would any other application from your system.