Hi @kiwi
To add selected document links to the category menu you'll need to add them manually
Open - amzin > templates > box.navigation.php
Find lines 29-31
{if $CTRL_SALE}
<li><a class="sale-link" href="{$URL.saleitems}" data-level="1" title="{$LANG.navigation.saleitems}"><i class="fas fa-tag"></i> {$LANG.navigation.saleitems}</a></li>
{/if}
Now just below it (before the </ul>) add your document links using the following structure
<li><a href="###LINKHERE###" data-level="1" title="Document One"> Document One</a></li>
To make the images responsive you'll need to remove the height/width styling from the html content and add class="img-responsive" to each of the image html elements.
To do this, click on the document page in the admin panel and select the content tab then add images as normal.
Then press the "source" button in the top left corner of the editor.
Your images will look something like :
<img alt="" src="/CubeCart/images/source/prod_01_a.png" style="width: 510px; height: 510px;" />
Now, remove the styling and add class="img-responsive"
so it would look something like
<img alt="" src="/CubeCart/images/source/prod_01_a.png" class="img-responsive" />