How do I present letsencrypt certificates to Kubernetes nginx (GKE)?

Question

I am learning the Google Cloud platform, trying to implement my first project and am getting lost in the tutorials. I am stuck at the trying to implement an nginx ingress. My ingress is stuck in CrashLoopBackoff and the logs show the following error.

I know how to do this task with DockerCompose, but not here.

Where do I start?

1#1: cannot load certificate "/etc/letsencrypt/live/blah.com/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/etc/letsencrypt/live/blah.com/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)
nginx: [emerg] cannot load certificate "/etc/letsencrypt/live/blah.com/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/etc/letsencrypt/live/blah.com/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)

I am not yet certain this is helpful, but I have set up the Certificate Authority Service (https://cloud.google.com/certificate-authority-service/docs/best-practices).