How does sqlalchemy work?

Question

Python

I’ll say right away that I don’t have much programming experience, now I’m trying to figure out the ORM sqlalchemy. Did I understand correctly that, in a nutshell, the point is that one row in the database table is represented as a separate object, where the values ​​of a separate column are attributes?
And yet, stupidly, but I just can’t figure out how to add a record to an existing database. Directly on steps, to create connection, then session?