You can only add footer widgets, not sidebars, to the presentation page (make sure they aren’t checked in the Hide Areas section).
Perhaps put your table short code in the visual editor within a WP page or post then use the indent tool to centre it (which adds left padding). Then use the text tab and copy the code into the Extra Text field, and adjust the padding value if needed.
I would very much like to have sidebar widgets on the presentation page. It’s awkward to expect people to follow or email subscribe if they must scroll to the footer area. It would be much more convenient to have various search parameters on the presentation page to help people find specific topics and posts. Please consider this is future updates.
You can use one of the columns to hold your socials/subscription form.
Although not very straightforward, the column texts can contain shortcodes, and there are plugins that allow you to create custom widget areas that you can then call using shortcodes.