About new plugin Attempted to load class

the doc say i can create plugin anywhere.
so firest i install sylius,and i create directory jinber/demo on vendor
then i run cd vendor/jinber/demo && composer create-project sylius/plugin-skeleton .

i did not change any thing,i run composer dump-autoload and composer install on vendor/jinber/demo directory

next, i add Acme\SyliusExamplePlugin\AcmeSyliusExamplePlugin::class => [‘all’ => true], to sylius config/bundles.php file

when i refrsh the sylius page i got error: Attempted to load class “AcmeSyliusExamplePlugin” from namespace “Acme\SyliusExamplePlugin”. Did you forget a “use” statement for another namespace?

why and how fix it? thanks