macOS will not open LetsVPN — what then? Personal Mac: System Settings → Privacy & Security → Open Anyway. Work Mac with managed wording: stop changing settings yourself. Give the dmg and this download page to an administrator.
Turning off SIP can look like a bypass until policy refreshes, and it leaves the machine unstable. That is not a path an install article should teach.
The client wants network-related permission
Enable the row the prompt names. Then connect a nearby node from the menu bar. Order: guide.
Install path: not iPhone steps. Need the file? Open Download.