Keep it running
Two ways to run the desk. Pick one. The one-line install already picked the second for you.
Start it when you want it
Double-click Start Desk in the desk folder (Start Desk.command on a Mac, Start Desk.bat on Windows), then open http://localhost:8765. A small window stays open while the desk runs. Close the window and the desk stops. Use this if you only want the desk while you are at the screen.
Always on
Double-click Keep Desk Running once (Keep Desk Running.command on a Mac, .bat on Windows). From then on the desk starts by itself when you log in, and if it ever stops, for any reason, it is back within a few seconds. Shut the laptop and it sleeps with it; open the lid and it carries on. You never start it by hand again.
The Settings screen carries the same switch, Start with the computer, and shows whether it is on.
Stop Desk switches the always-on desk off. On a Mac, double-clicking it again switches it back on; on Windows, double-click Keep Desk Running again.
What is behind it
On a Mac it is a launch agent, a small file at ~/Library/LaunchAgents/com.research-desk.plist that tells macOS to run the desk at login and restart it if it exits. On Windows it is a task named "Research Desk" in Task Scheduler that runs a hidden PowerShell script at logon. On Linux it is the systemd user unit greeksoup-desk.service. Nothing else is installed anywhere on your computer.
Two copies of the desk on one computer share the service name, so the switch on one copy stays out of the way when the other owns the service, and says so.
How to tell it is running
The address opens. If the page is blank, the page is blank has the steps in order.
What happens in daily life
You shut the computer down and switch it on again, and the desk is back once you log in. You close the laptop lid, the desk sleeps with it and carries on when you open it. Something crashes, the desk restarts itself. Nothing on the desk needs a login of its own; only a broker whose regulator requires a fresh login every trading day asks for anything in the morning, and that is on the broker's page.