How to set limits for the containers in k8s

I have a gitlab runner in my k8s cluster. I installed it with gitlab integrations. First helm then gitlab-runner.

I want to set limits and requests for service/build/helper containers.

I've read https://docs.gitlab.com/runner/configuration/advanced-configuration.html and this https://docs.gitlab.com/runner/executors/kubernetes.html#define-keywords-in-the-config-toml

And I've seen others' issues like https://stackoverflow.com/questions/54707598/how-to-customise-config-toml-on-kubernetes

I have a problem. Whenever I add those "keywords" they are whether ignored or makes duplicates of the sections in /home/runner..../config.toml

I request a simple howto. How to set request/limits for k8s containers.