How to install istio in private network without access to internet?

I install istio in private network, that have no access to internet.
I can pull images from public repositories as kubernetes.io, docker.io etc and push it in out private docker registry, then use it for deployments.
But i cannot find how to specify this our private docker registry in istioctl?
When i do
istioctl install --set profile=demo -you
I see Err Image Pull Back Off:
Warning Failed 56s (x2 over 76s) kubelet Failed to pull image "docker.io/is to/pilot:1.13.3": rpc error: code = Unknown disc = Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io: Temporary failure in name resolution
How to tell istioctl to pull images from our private docker registry? And how to get list of images for copy it in our registry?