How to allow nova resource action in Policy

Nova 2.0 Laravel 5.8

I have one nova resource Document ( contains file url, related foreign key and title ) for which I have defined policy with create and update false and all others set to true, the PDF is generated from another resource, so I don't need to allow it to be created or edited, now everything is working fine, but with another action on this Document resource I am trying to download these files, giving me error "Sorry you are not authorized to take this action", so how to allow this action on Policy.

DocumentPolicy class

<?php

namespace App\Policies;

use App\User;
use App\Models\Document;
use Illuminate\Auth\Access\HandlesAuthorization;

class DocumentPolicy
{
    use HandlesAuthorization;

    /**
     * Determine whether the user can view any documents.
     *
     * @param  \App\User  $user
     * @return mixed
     */
    public function viewAny(User $user)
    {
        return true;
    }

    /**
     * Determine whether the user can view the document.
     *
     * @param  \App\User  $user
     * @param  \App\Document  $document
     * @return mixed
     */
    public function view(User $user, Document $document)
    {
        return true;
    }

    /**
     * Determine whether the user can create documents.
     *
     * @param  \App\User  $user
     * @return mixed
     */
    public function create(User $user)
    {
        return false;
    }

    /**
     * Determine whether the user can update the document.
     *
     * @param  \App\User  $user
     * @param  \App\Document  $document
     * @return mixed
     */
    public function update(User $user, Document $document)
    {
        return false;
    }

    /**
     * Determine whether the user can delete the document.
     *
     * @param  \App\User  $user
     * @param  \App\Document  $document
     * @return mixed
     */
    public function delete(User $user, Document $document)
    {
        return true;
    }

    /**
     * Determine whether the user can restore the document.
     *
     * @param  \App\User  $user
     * @param  \App\Document  $document
     * @return mixed
     */
    public function restore(User $user, Document $document)
    {
        return true;
    }

    /**
     * Determine whether the user can permanently delete the document.
     *
     * @param  \App\User  $user
     * @param  \App\Document  $document
     * @return mixed
     */
    public function forceDelete(User $user, Document $document)
    {
        return true;
    }

    public function download(User $user, Document $document)
    {
        return true;
    }
}