Lesson 8. Theoretical Doubt: Relation between PV and PVC

Hello everyone.
How are you all doing?

I am doing the labs for lesson 8: VOLUMES AND DATA and I have a question. I don't understand how the persistentVolumes are related to the PersistentVolumeClaim.
I mean, if I create a PV:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pvvol-1
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:
    path: /opt/sfw
    server: k8scp
    readOnly: false

I can see that it is not claimed by anyone.

~$ kubectl get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pvvol-1   1Gi        RWX            Delete           Available                                   87s

Now if I create a PVC:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-one
spec:
  accessModes:
  - ReadWriteMany
  resources:
     requests:
       storage: 200Mi

Now I can see that the PV is claimed by the PVC pvc-one.

~$ kubectl get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM           STORAGECLASS   REASON   AGE
pvvol-1   1Gi        RWX            Delete           Bound    small/pvc-one                           2m47s

But I have not specified that the PV pvvol-1 is claimed by pvc-one. So how are they related?

Thank you very much and best regards.