You should run git clone on the server with installed k3s.

kubectl create -f files/charts/cert-manager.yaml 

kubectl create -f files/resources/cluster-issuer.yaml

• Provide your domain instead of dex-demo.***
• Provide your gitlab app clientId and clientSecret
• In groups set your existing gitlab group
• Deploy chart with the following command

kubectl create -f files/charts/dex.yaml

cp files/k3s-config.yaml /etc/rancher/k3s/k3s.yaml
systemctl restart k3s

kubectl create -f files/resources/cluster-role-binding.yaml

TODO: describe how to try auth with kubeconfig and with the browser