First you must have kubectl and Argo-cd intalled on your oci's cluster
https://argo-cd.readthedocs.io/en/stable/getting_started
Second, create app in Argo-cd server and write your custom namespace on "destination" space
After syncing, write on browser:
http://144.22.248.251/testando/health
It shoud return
"OK"
Where above ip is your LoadBalancer external ip, if you don't know, write:
kubectl get ingress --all-namespaces
or
kubectl get ingress -n <your_namespace>