Progressive overload is the whole reason any of the programs on this page work: your body only has a reason to get stronger if you keep asking it to do slightly more than it's used to. That's it — everything else is detail.
What "more" actually means
More weight is the obvious lever, but it's not the only one. More reps at the same weight, more sets, less rest between sets, or better technique that lets you feel the same muscle work harder all count. On a bad week, just holding your numbers steady while everything else in life is hectic is still a win — it's the months-long trend that matters, not any single session.
How to apply it without overthinking it
Pick a rep range for each main lift and try to add either a rep or a small amount of weight every session or two. When you can't add anything for two or three sessions running, that's your cue to either hold at that weight for a week or drop back slightly and build up again — which is exactly what the deload wave in the powerbuilding program above is doing on purpose.