Open your.os
Your browser makes a key and you land on a random name of your own, like
brave-otter-42. The key is the account. It is made in the tab and never
sent anywhere.
Add a machine
Paste one line into a terminal on the machine you want to reach. The code is single-use and expires in ten minutes.
curl -fsSL https://your.os/install | sh -s brave-otter-42-7Q4KThe machine joins your account and appears in your devices, with what it's allowed to do.
Open a terminal
Click the machine. You're in a shell on it, sealed end to end, through whatever network you're on. Close the lid, change wifi, and it carries on.
Keep it
When you have something worth keeping, pick a name and add a passkey. Until then your account lives only in this browser. Add a second device too: losing every device means losing the account.