willbro

You said the dashboard was “pretty much blank”. That’s too vague for you to be helped.

If you (as admin) or your user (as contributor) don’t see anything (or at least see the Posts tab, then:
Your install could be broken.
The permission to “write” might be limited (by the server file system).
But you should check out this page on how to write posts

https://codex.www.ads-software.com/Writing_Posts

You can do this two ways:

1. Allow them to create a “post” on your site
2. Allow them to comment on a “post” on your site

Option 1
They are being given a higher level of user access to the site, at least “contributor”, rather than say “subscriber”.

Option 2
You can allow people to comment without being registered users, or even providing a name and email address. But things will get messy.

You will need to read the instructions for WordPress to find these settings for new users, and or commenters. Good luck!