How to access Container registry in Gitlab-ce in Docker

Hi Guys

i am facing a hard Task since Weeks. The Goal of this Task is, to use the Gitlab integrated Container Registry

My Current Setup:
Synology NAS → Docker Container (Gitlab-ce)
also installed is portainer

current Gitlab Config File:

external_url 'https://MyPublicNasUrl:MyPublicNasPort'

nginx['listen_addresses'] = ["0.0.0.0", "[::]"]
registry_nginx['listen_addresses'] = ['*', '[::]']
mattermost_nginx['listen_addresses'] = ['*', '[::]']
pages_nginx['listen_addresses'] = ['*', '[::]']
nginx['listen_port'] = 80
nginx['listen_https'] = false
nginx['redirect_http_to_https'] = false
registry_nginx['redirect_http_to_https'] = false
mattermost_nginx['redirect_http_to_https'] = false


#registry_external_url 'I_Have_No_Idea'
#gitlab_rails['registry_enabled'] = true
#gitlab_rails['registry_host'] = "localhost"
#gitlab_rails['registry_port'] = "10005"
#
#
#registry['enable'] = true

what do i have to do, to enable the container registry, and what i have to do, to get access to it?