The only trick with reusing LIbGuides boxes is that you have to know what guide has the master version of the box. Unlike LibGuides ver. 1, you can't reuse a box that is itself a mapped copy.
Video: Reusing Ask Us Widgets In LibGuides 1:47
Copy this code into the "Other Widget Code" box in your LibApps profile. Set "Display Options" to "Page & Box". This code can also be used to include the small Ask Us widgets into the HTML of any of your pages.
<iframe id="s-lg-widget-frame-1584654546635" width="100%" height="275" scrolling="no" frameborder="0" style="border: 0px solid transparent;" src="//lgapi-us.libapps.com/widget_box.php?site_id=20&widget_type=8&output_format=2&widget_title=Ask+Us%21&widget_height=270&widget_width=100%25&widget_embed_type=1&guide_id=679095&box_id=15978213&map_id=18822534&content_only=1&config_id=1584654546635"> </iframe>
Embedded, it displays as follows: