Before we change anything, it's worth seeing the machinery. Nearly everything in this program comes down to two systems, and once you can see them, most bad nights stop being mysterious.
From the moment you wake, a chemical called adenosine accumulates in your brain, and the longer you stay awake, the heavier the pull toward sleep, like a battery draining. By bedtime you're carrying roughly sixteen hours of built-up pressure. Sleep is the release valve: overnight the adenosine clears, and you wake with an empty tank, ready to fill again.
Two everyday things tamper with this system:
Your circadian rhythm is a roughly 24-hour timer that decides when your body expects to be awake or asleep. It runs on light: bright mornings set it, and dark evenings release melatonin.
You already know this clock from the inside. The dip around two or three in the afternoon is the clock. So is the strange second wind at nine or ten pm, when you were exhausted an hour earlier — not randomness, just the clock's built-in evening alerting signal running on schedule.
Good sleep happens when the two systems line up: high pressure meeting the clock's open gate. When they line up, sleep stops taking effort; it arrives on its own, like a wave you catch.
Insomnia is usually these systems out of sync. Pressure spent early by a nap or a lie-in. A clock scrambled by irregular hours or late-night light. If that's you, you've been trying to force sleep while the machinery underneath wasn't ready, and no amount of trying fixes that. It's not a character flaw; it's an alignment problem, and everything in the next six weeks, every rule and every schedule change, is about realigning the two systems — mechanics rather than tricks.