Training for seasoned DBAs new to postgres?

Good day!

We have a group of Oracle and MS SQL Server DBAs who are looking to get a
jump start on postgres. Would anyone here have recommendations for
high-quality postgres training that focuses on administration
(architecture, filesystem layout/optimization, install, configure,
update/patching, backup and restore, user security, performancing tuning)?
Most of the training that I have been able to find so far are more along
the lines of "zero to hero", with a lot of focus on sql.

We are in Illinois, and I see that there is a Postgres user group in
Chicago, but the website listed on the User Group community page seems
defunct.

Thanks for your time and attention.

--
Charles Schultz