Dunno if there is a better way, but you could make docker-compose.yml from the existing/running containers: https://www.makeuseof.com/create-docker-compose-files-from-running-docker-containers/ and import those into Portainer.
P.S. I haven't tried this.
Dunno if there is a better way, but you could make docker-compose.yml from the existing/running containers: https://www.makeuseof.com/create-docker-compose-files-from-running-docker-containers/ and import those into Portainer.
P.S. I haven't tried this.