NetApp has a 7-mode migration tool you can also use to do this. CLI manually seems easier to me. You don't have to install software anywhere. This assumes you have the intercluster lif ip addresses added to the 7-mode controller's snapmirror.allow file. You cannot snapmirror between the systems without an intercluster lif on the CDoT system. You will need an intercluster lif on each node in the cluster that can route to the 7-mode system.
1. Create a transition peer relationship
vserver peer transition create -local-vserver <cluster name> -src-filer-name <7-Mode Controller>
2. Create the volume to use for the mirror on the cluster side.
volume create -vserver <SVM on cluster> -volume <mirror name> -aggregate aggr1_01 -size 4t -space-guarantee none -percent-snapshot-space 0 -type DP
This creates a thin provisioned volume on the storage virtual machine that will eventually be using this volume. The aggregate, size, naming will be specific to your environment.
3. Create the snapmirror relationship, type, and schedule.
snapmirror create -source-path <7-mode controlle>:<source volume> -destination-path <svm>:<snapmirror volume> -type TDP -schedule hourly
4. Initialize the mirror
snapmirror initialize -destination-path <svm>:<snapmirror volume>
Once the initialization completes it will sync on the hour if you chose hourly.
You see the progress by using snapmirror show. Keep in mind CDoT does not constantly update the stats so you may not see change for 5 minutes or so. If you want more live stats, you can do a snapmirror status on the 7-mode controller.