The concept for child plugin doesn't really work with. With child theme's you inherit the CSS, functions, template, etc.
But as a plugin can do pretty much do anything, it's hard to determine what to inherit. :)
if I modify the plugin and later there is an update for that plugin
If you modify it, update the
Plugin Name: and
Version: in the plugin header and that should* avoid updates overwriting your changes.
If you want to modify the output or behavior of that plugin, that's more fun (and educational BTW). You can make another plugin that adjusts the output via
add_filter(), remove and re-add the plugin's shortcode, etc.
That way if the original plugin get's updated, as long as the way it works remains the same, your modify plugin will probably still work.
*I have to check that part. I think bumping up the version number to ludicrous numbers will prevent an update too.