My only exposure to electrical theory was 60+ years ago in 10th grade physics. My practical experience did not run to breadboards, jumpers, LEDs (see my previous post), etc. Internet content is great for ease of access but can occasionally be wrong. The breadboard images below make things pretty clear. The left side is less interesting than how the holes are really interconnected underneath.
The bad info I got stated that the vertical outer columns were NOT connected across the gaps that occur every 5 rows. I did some really dumb jumper-ing while I momentarily believed that.
Because of age-related presbyopia I could really use a "large print" version of the breadboard. But that's never going to happen so I keep the magnifying glass close.