After installing both Concrete Wall and Concrete Wall Share, add Concrete Wall Share as a block to a page (home page or profile page).
Add Concrete Wall (use the site-wide activity option) as a block directly below the Concrete Wall Share Block within the SAME AREA.
Apply the custom template of 'Commentable' to the Concrete Wall. This template will only work if both of the steps above are done.
Publish your edits and begin wall posting!