Correct errors and add backup slides (!3)
See merge request !3
Correct error, fix style issues, and add more backup slides.
Apply revisions and address comments on CDS for the ATLAS internal practice talk
c.f. https://cds.cern.ch/record/2707909/ version 4
Add draft of talk that was submitted for ATLAS internal review
as ATL-COM-PHYS-2020-048 (https://cds.cern.ch/record/2707909).
See merge request !1