Удобнее всего установить это расширение через composer.
"pavlinter/yii2-adm-mailing": "*",
'modules' => [
...
'adm' => [
...
'modules' => [
'admmailing'
],
...
],
'admmailing' => [
'class' => 'pavlinter\admmailing\Module',
],
...
],
'components' => [
...
'mailer' => [
'class' => 'yii\swiftmailer\Mailer',
'transport' => [
'class' => 'Swift_SmtpTransport',
'host' => 'localhost',
'username' => 'username',
'password' => 'password',
'port' => '587',
'encryption' => 'ssl',
],
],
...
],
yii migrate --migrationPath=@vendor/pavlinter/yii2-adm-mailing/admmailing/migrations