use Tassili\Crud\Fields\MultipleFile;

MultipleFile::make('files')
  ->label('New label') // optional
  ->notInDatabase() // optional, if you don't want this field in database
  ->fieldAndRecordNotNull() // optional, if you want to have at least one file in record or in field
  ->keepExistingFiles() // optional, if you want to keep existing files
  ->readOnly() // optional, if you want the field only readable when you update 
  ->folder('posts/images') // optional, if you want to change the folder storage 
  ->maxNumberFiles(3) // optional, if you want to limit the number of files

               
use Illuminate\Database\Eloquent\Model;

class Post extends Model
   {
   protected $casts = [
   'files' => 'array',
   ];

         }

->fieldAndRecordNotNull()