In order to SSH into a worker node, you first have to find the external IP address of the node:
$ kubectl get nodes -o wide NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME ip-172-31-19-107.eu-west-2.compute.internal Ready <none> 22s v1.15.6 172.31.19.107 126.96.36.199 Ubuntu 18.04.3 LTS 4.15.0-1054-aws docker://18.9.2 ip-172-31-20-156.eu-west-2.compute.internal Ready <none> 21s v1.15.6 172.31.20.156 188.8.131.52 Ubuntu 18.04.3 LTS 4.15.0-1054-aws docker://18.9.2
You can use the external IP to ssh into the node using the SSH key you added as described in add an SSH key under project management section.
ssh -i ~/.ssh/id_rsa firstname.lastname@example.org
Note that some providers (e.g. Digitalocean) don’t allow SSH access to worker nodes.