Using Secrets in a VS Code dev container on Rancher Desktop

I want to use secrets (in this case a private SSH key) in my VS Code Development container, and so far I am struggling to understand how to make this work. I am running Rancher Desktop on my Macbook and configured the secret in there (added it to the default namespace), but I have no clue how to make it available to my dev container. I guess more specifically I do not understand how (or if) my dev container has any relation to the default namespace in Rancher Desktop.