The || icon to turn on and off the display of the right and left columns on the Portal page is shown at the upper right next to the "Search" magnifying glass icon. Click on that icon to show or hide the right and left columns on the Portal page. Those side columns are hidden by default on narrow screens such as a phone held vertically. You can click on the column icon || to view the side columns, but you'll have to scroll sideways to see them, or hold your phone horizontally.
Remember that "Petro Recent Posts" does not list all forum section posts. Click on "Active Threads" on the main menu bar to see all recent posts.