How to add icon to linemarker?

Hello, followed this tutorial https://www.jetbrains.org/intellij/sdk/docs/tutorials/custom_language_support/line_marker_provider.html. 

i created my class for my marker, but when and where i need to call this class to add icon to line? can you help me? In best case i would like to add icon next to line when i edit current line, i work here with PsiTreeChangeListner. Thanks for help, i am new to this.

public class CustomLineMarker extends RelatedItemLineMarkerProvider {
    @Override
    protected void collectNavigationMarkers( @NotNull PsiElement element,
                                             @NotNull Collection< ? super RelatedItemLineMarkerInfo > result ) {

            NavigationGutterIconBuilder< PsiElement > builder =
                    NavigationGutterIconBuilder.create(IconLoader.getIcon("resources/META-INF/fail.png"))
                            //TODO ADD PSI ELEMENT
                            .setTargets( element )
                            .setTooltipText( "Navigate to Simple language property" );
            result.add( builder.createLineMarkerInfo( element ) );

    }
}
```