Documentation confusing, attach to running program using processId

[meanpossum]

Attach to process
Attaching to existing processes currently only works by specifying the processId in the launch.json and setting request to "attach". You also need to specify the executable path for the debugger to find the debug symbols. If the argument program arg is not set, a pickprocess window will be displayed. If the argument program is set and only one process is found ,the debugger will start automatically.
{
    "type": "by-gdb",
    "request": "attach",
    "name": "Attach(gdb)",
    "program": "{fileBasenameNoExtension}",
    "cwd": "${workspaceRoot}"
}
This will attach to 5678 which should already run.

Which parameter is processId set in ? Example does not actually show 5678 being used.
I need to attach to an already running program that I cannot re/start on a remote device.

Thankyou.