by default the .htdocs file cannot route the traffic to index.php this needs to be changed in the Apache config file to make it work:

<Directory "C:/xampp/htdocs/public">    # route to the public folder
    Options Indexes FollowSymLinks
    AllowOverride All                   # allow override
    Require all granted
</Directory>

the costum routes can be set in the /routes/api.php file in the following format:

'$METHOD $URL' => [$class::class => $function_as_a_string]

for example:

'GET /user/get' => [UserController::class => 'get_user'];

if you need to encode a id or dynamic data into the url you can use the {} tag to route all matching parameters for example:

'GET /user/image/{id}' => [UserController::class => 'serve_image'];