Subscription Manager Shows "Not Subscribed"

Installed RHEL 7.8 and follow guide but still cannot get subscriptions to attach properly

[root@localhost ~]# subscription-manager list
+-------------------------------------------+
Installed Product Status
+-------------------------------------------+
Product Name: Red Hat Enterprise Linux Server
Product ID: 69
Version: 7.8
Arch: x86_64
Status: Not Subscribed
Status Details:
Starts:
Ends: