private function loadForm()
{
// get group values for dropdown
$ddmValues = BackendProfilesModel::getGroupsForDropDown($this->id);
// create form and elements
$this->frm = new BackendForm('import');
$this->frm->addDropdown('group', $ddmValues);
$this->frm->addFile('file');
$this->frm->addCheckbox('overwrite_existing');
}