Type "adcl" in the command line and press enter or click on the app ribbon button at the Add-ins tab. A dialog box will appear. You can define the distance between elevation texts along each polyline, the tolerance length of polylines to insert elevation text (polylines less than tolerance will not label), a layer to filter polylines to insert elevation text, the text height, elevation precision, text style, text layer and also choose if you want to break the polylines around the elevation texts.

Important: if you choose to break the contour polylines around the elevation texts, it may take a long time if the polylines have many vertices.

The installer that was run when you downloaded this app/plugin from Autodesk App Store will start installing the app/plugin. OR, simply double-click the downloaded installer to install the app/plugin. You may need to restart your Autodesk product to activate the app/plugin. To uninstall this plugin, 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 system application.

This app works only with polylines. It doesn't work with 3dpolylines, lines, arcs, circles, or other objects. If you choose the option "Break contour lines" in the dialog box, it may take a long time if the polylines have many vertices.