[MrRadar]

For how they know where to point, that's something that's calibrated individually for each set. Typically the initial calibration is done at the factory (or, if you've done a major service on a set, by the technician who did the service) and then tweaked by the end-user to their own preferences. That's why all CRT displays have adjustments at least for hoizontal and vertical size and position (offset). Fancier displays have even more adjustments for other geometric corrections like pincushion and keystone.

Here's a video demonstrating how to do a full setup (calibration) on a vintage color CRT (timestamp 16:02 for the start of the procedure): https://youtu.be/Oeylkj1vap8?t=962