Special modifications had been made to the Star's 1620 to allow it to be an early form for multi-tasking. If an accounting program was being processed, it could be automatically interrupted by a paper tape reader. The entire memory would be written to disk, and the typesetting system loaded. When typesetting was done, and no other paper tape readers waiting, the accounting task would be read back into memory and processing would resume automatically from where it had been interrupted. Back then we thought that was cool!
News copy was punched into 6-channel teletype paper tape, then processed thru the IBM 1620 for hyphenation and justification, and was output to punched paper tape. The output tape was then mounted on the Linotype linecaster's reader, enabling hot-metal type to be generated at about 12 lines per minute.
Individual lines of type were gathered together in a galley, then placed by hand into a makeup tray. Art work was also processed by hand (another involved process including camera work, chemistry and plate making) and converted into plate-covered wood blocks, that were then placed into the tray. Then when everything on the page was in place, the makeup tray was "locked up" and a mold made.
Then the mold was placed into a machine that formed a half-cylinder of lead containing the impression from the mold. This process was repeated for every page in the newspaper. These cylinder were then mounted onto the presses, and that's how the Kansas City Star newspaper was produced in the mid-60's.
The Star was also one of the first papers to install a Mergenthaler Linofilm, one of the first machines to image photograhic film. Until a special controller was developed, it required 15-channel paper tape. So special paper tape punch machines were custom-made. The special controller later added converted 6-channel paper tape input into the required 15-channel information required.
Obviously, there were a lot more steps and details in the process, but this would almost be a book in itself.
If you want to know more about Ottmar Mergenthaler, the founder of Linotype, be sure to visit Linotype History.