Install the host on the computer you want to reach. Pair it once, then connect from any browser, anywhere.
Open the .dmg and drag Alluno into your Applications folder.
Allow Screen Recording and Accessibility when Alluno asks.
Launch Alluno. It shows a Device PID and a pairing code; enter them in the browser you want to watch from.
Alluno prints a Device PID and a pairing code the first time it runs, with a QR of both. Enter them at alluno.io from the browser you want to watch from, or scan the QR with a phone.
Once the machine is paired it appears in your dashboard. Open it from a laptop, a tablet or a phone, at that machine's own resolution.