Engelbart and his team presented for about an hour and 40 minutes. The talk consisted of, among other things, the first public demonstration of a computer mouse. It introduced WYSIWYG editing. It showed off hypertext. It demonstrated the graphical user interface. Engelbart and his colleagues explained these new technologies; they also employed many of them as part of their presentation. (A young Steward Brand acted as one of their camera operators.) For people who had been used to thinking of computers as little more than fancy calculators, the whole thing was fairly mind-blowing.
Although most people probably use a touch screen to interact with computers, such as smartphones, we still rely heavily on a graphical interface. I would guess that fewer than 5% of current computer users have ever dealt with a command line. We have also adopted navigating from one page to another as an everyday part of our computing experience. The web as we know it wouldn’t be a reality for another twenty-two years.
Speaking of taking things for granted, you can watch a video of this presentation on YouTube.