Trying to add a Unity Catalog for use in Azure Databricks, but receiving the error message “No metastore assigned for the current workspace.”

(https://i.sstatic.net/0kOkJYmC.png)

I have checked that I am a workspace admin in Databricks. Other explanations on the web say that there is a workspaces tab when navigating to the catalog section, however, I do not see this.