Version v0.39 of Metabase is no longer supported. Check out the docs for the current stable version, Metabase v0.63.
If you are using a Metabase version earlier than 0.33, you will need to either write a SQL query that contains joins, or have your Metabase administrator set up foreign keys (they can read more about that here).
If you are using Metabase 0.33 or above, you can perform joins using the Notebook editor.
