Nextjs Learn 15 - Auth issue with signIn

[getzelus]

The tutorial says to add this line in lib/actions.ts :
import { signIn } from '@/auth';
but i have this error message :
Cannot find module '@/auth' or its corresponding type declarations.ts(2307)

The path seems strange so i change by :
import signIn from 'next-auth';
and try to login with this credentials (as in the tutorial) :
Email: user@nextmail.com
Password: 123456

But in lib/actions.ts i have bug with this line :
await signIn('credentials', formData);
error message :
Error: Cannot create property 'basePath' on string 'credentials'