Doubts on how to do joins between tables in the metabase

I would like to know how it is possible to do joins in Metabase in the interface to builder?

For the Metabase core teams view on why they just didn't add joins front and center see these blog posts:

So, you can still do joins inside Metabase - it's just they sort-of hid it away for most users as "native SQL questions"... in particular I'd say the "Questions in Questions" approach combined with SQL knowledgeable users doing fancy stuff as pre-cooked qustions to build on for others is powerful.

The thread below may also shine some light on the topic - and how some of the (somewhat related) related PK-FK mapping shines trough in the UI

I hope that answers some of what you were asking?