This example follows QMK's Community Modules and External Userspace layouts.
Copy firmware/modules/opencontrol to <QMK_USERSPACE>/modules/opencontrol.
Then merge the files below into your real path:
<QMK_USERSPACE>/keyboards/<keyboard>/keymaps/<keymap>/
The your_keyboard directory is documentation, not a build target. Keep the
keyboard manufacturer's existing keymap.c and VIA definition. Merge the
modules array from keymap.json and the settings from config.h.
In VIA, map the selected layer to F13–F24 and shifted F13–F19 as described in
firmware/PROTOCOL.md. A layer key such as MO(3) must remain reachable from
another layer.
Compile with the normal External Userspace command for your exact keyboard:
qmk config user.overlay_dir=/absolute/path/to/qmk_userspace
qmk compile -kb <keyboard> -km <keymap>Do not flash until the keyboard, revision, bootloader, and recovery procedure have all been verified.