The app for his laptop
Install it on the computer he does homework on. It adds a “Homework Gate” printer, so anything he prints there lands in tonight's list, and sets up the lock for his free time.
Windows · Windows on ARM · Mac
After it downloads
Windows: if a blue “Windows protected your PC” box appears, choose More info, then Run anyway. Say Yes when it asks for permission.
Mac: open the download, drag Homework Gate to Applications, and open it from there. If macOS says it can't check it, open System Settings, Privacy & Security, and choose Open Anyway.
It shows a code and a QR code. Scan it with your phone, signed in as the parent, choose your child, and tap Link.
It sets itself up: the Homework Gate printer and the lock. From then on it starts by itself.
Why the warnings: the apps aren't signed yet with Apple's and Microsoft's certificates. That's coming; the warnings go away then.