The docs in the following section:

https://docs.openshift.com/gitops/1.13/argocd_instance/setting-up-argocd-instance.html#gitops-deploy-resources-different-namespaces_setting-up-argocd-instance 

Include instructions for adding the managed-by label include the following:

$ oc label namespace <namespace> \ 
argocd.argoproj.io/managed-by=<namespace> (1)

1) The namespace where Argo CD is installed.

This is a little confusing because the <namespace> for the first line is going to be different from the label in the second line.

Instead, it would be great to have something like this:

$ oc label namespace <target-namespace> (1) \ 
argocd.argoproj.io/managed-by=<argocd-namespace> (2)

1) The namespace you wish Argo CD to manage.

2) The namespace where Argo CD is installed.