I like the Washington Post's explanation of this https://www.washingtonpost.com/politics/2019/03/15/beto-orourkes-hacking-universe-explained/?utm_term=.0b9e2d0b9d53
At the time that ORourke was engaged with the group, the Internet wasnt the Internet we have today. This was the late 1980s, and it wasnt until the early 1990s that Americans began to regularly use something like the Internet as we understand it now, connecting over networks to pages on the Web. ORourke wasnt sitting in front of a computer and clicking a Web browser. In fact, he wasnt clicking anything.
What ORourke was using was a bulletin-board system, or BBS, which is to the Web what going to a restaurant is to going to a food festival. A food festival thats also on Seamless.
How much of this is familiar to you will depend on how old you are. You may, for example, remember modems, little boxes attached to your computer or (in later years) built into it, into which youd plug a regular phone landline. (If you dont know what a phone landline is, which seems plausible, its the physical cord that ran phone lines into houses before cellphones became ubiquitous.) The modem converted a signal that could run over a phone line into one that a computer could recognize.
In the early days of the Internet, people used modems to connect to Internet service providers (ISPs), which would connect them to the broader Internet. But in the BBS era, modems were used to connect directly to other computers that were running software that could host small communities of users. To connect, you would actually call a specific phone number with your computer and connect to the computer hosting the BBS.
This story actually makes me like Beto more.
BTW, I still remember using something called mag cards and floppy disks to revise documents.