How do I wire my form action to my controller action? I'm writing my first Craft CMS plugin.

I have the following tag in my form:

&lt;input type="hidden" name="action" value="clientnameDonation/donateForm/donate"&gt;


And then I have the following controller code to handle the action:

namespace Craft;

class ClientnameDonation_DonateFormController extends BaseController
{
    protected $allowAnonymous = array('actionDonate',
        );

    public function actionDonate()
    {
        // stuff
    }
}


When I try to submit the form, I get the following error:


  Unable to resolve the request "clientnameDonation/donateForm/donate"


Is there a piece I'm missing, or is there a casing error somewhere?

I also tried just using a raw action URL like this:


  http://URL/index.php?p=actions/clientnameDonation/donateForm/donate


I get the same routing error.
I had the plugin set up correctly but I didn't go into the administration menu and install the plugin via the GUI.