I'm ashamed to say it but I cannot for the life of me understand how kustomize works. I could not ever figure out how to do things outside the "hello world" tutorials they walk you through. I'm not a stupid person (citation needed lol), but trying to understand the kustomize docs made me feel incredibly stupid. That's why we didn't go with that instead of Helm.
Helm requires you to write a template and you need to know (or guess) up front which values you want to be configurable. Then you set sane defaults for those values. If you find a user needs to change something else you have to edit the chart to add it.
With Kustomize, on the other hand, you just write the default as perfectly normal K8s manifests in YAML. You don't have to know or care what your users are going to do with it.
Then you write a `kustomizatiom.yaml` that references those manifests somehow (could be in the same folder or you can use a URL). Kustomize simply concatenates everything together as its default behaviour. Run `kubectl kustomize` in the directory with `kustomization.yaml` to see the output. You can run `kubectl apply -k` to apply to your cluster (and `kubectl delete -k` to delete it all).
From there you just add what you need to `kustomization.yaml`. You can do a few basics easily like setting the namespace for it all, adding labels to everything and changing the image ref. Keep running `kubectl kustomize` to see how it's changing things. You can use configmap and secret generators to easily generate these with hashed names and it will make sure all references match the generated name. Then you have the all powerful YAML or JSON editing commands which allow you to selectively edit the manifests if you need to. Start small and add things when you need them. Keep running `kubectl kustomize` at every step until you get it.
