From Factba.se, here's what Trump was saying in Lumberton:
If Joe and Kamala are elected, it will trigger a tsunami of illegal immigration from every corner of the world. Tens of billions of people will flood into our country. You're not going to be too happy in North Carolina.
...For the last half a century, Joe Biden's been outsourcing your jobs, opening your borders, and sacrificing American blood and treasure and endless and ridiculous foreign wars. I fight for the middle class and Biden and his cronies serve only one class. They serve the donor class, believe it or not. Now, in all fairness to donor class, I would be the greatest in history.
Under my leadership we achieved the most secure border in US history, our southern border, and we're finishing the wall. 400 miles plus, already built. Think of that. 400 miles. You know what 400 miles is? That's a lot. We'll be finished very shortly and it's exactly what they wanted. This is -- I said to the Border Patrol, "Give me your best, give me -- just give it." I figured it would be a nice concrete plank.
Boom, boom, boom, right? Precast. That was my business. I was really good at that business. So I looked -- I sort of saw a concrete plank, boom. And it turned out, they don't want that. They want steel and concrete, and they want vision, and they want all sorts of things. But in the end they were right, I wanted to give them what -- we're doing it, we might as well do it right. More expensive, but we might as well do it right. So we gave them a wall that is not penetrable, and its got hook ups to every form of commun -- of computer known to man, right? Remember when they said the wall, the wall is a wall, it's obsolete. I said, "No, walls are not obsolete." Two things, right? Walls and wheels will never be obsolete.
Speech: Donald Trump Delivers Remarks in Lumberton, North Carolina - October 24, 2020
By the way, a lot of border fencing is going up, in spite of no help from the GOP, and lawfare by the Treason Lobby. If it doesn't look like what we imagined a "Great Wall of Trump" may look like, there may be a good reason for that. See from 2015, Steve Sailer's Why Trump Fence Would be Better Than Trump Wall in which he points out that Israelis use what would better be described as a fence.