Install via the Control Panel or via composer

composer require sortarad/facepalm

Create directory sortarad in addons directory and clone project there.

In your project root’s composer.json, add your package to the require and repositories sections, like so:

{
    "require": {
        "sortarad/facepalm": "*"
    },
    "repositories": [
        {
            "type": "path",
            "url": "addons/sortarad/facepalm"
        }
    ]
}

Run composer update from your project root (not your addon directory).

composer update

Add widget to control panel configuration config/statamic/cp.php file.

e.g:

[
	'type' => 'facepalm',
	'width' => 50,
],