What was programming like before the internet?
quora.com
quora.com
2: find, in amongst other articles; "Intergalactic Battle Cruiser Hyper wars -free game code!" accompanied by lurid illustration showing apocalyptic space battle, replete with explosions, mighty spaceships and exotic green-skinned women in silver bikinis
3: Spend several hours laboriously typing the 3 or 4 pages of closely printed code, line by line, into your Amiga/Spectrum/Dragon/Oric/BBC Micro*
[delete as appropriate]
4: Run programme
5: "Syntax Error: Line NNN"
6: Fix Line NNN
7: Repeat stages 4 -6 several dozen times
8: Run Programme without it crashing --yay!
9: Letters XX>* move slowly across screen from left to right... Press spacebar... Letter O moves up screen from bottom to top and hits letters XX>... Computer makes feeble buzzing noise, like a bluebottle's fart... Letters disappear... Screen prints "GAME OVER! --PLAY AGAIN? Y/N"...
10: Hit "N" and go outside and play football with your mates.
Info came through magazines, word-of-mouth, or later BBSes/usenet newsgroups (like shared email) received a couple times a day. So we were voracious for it, hang out in game/computer stores to talk to people.
Knowing/remembering was automatic as there was no other way. Always wrote/debugged programs from your head only looking up a few memory addresses you weren't sure about. Could assemble (small program) instructions to machine code in your head, and convert to 8-bit string. Get string address and 'call' it. Going to each others' houses to show n tell or pair program and play video games that we made, bought, or cracked.
Human-based customer support still exists today, at least for expensive enterprise software. Companies actually pay for yearly support contracts so they can get their questions answered and get help with technical issues.