When we say "get back to the old times" it sounds like we mean go back in time with a time machine, but often it seems to be used figuratively? Is it one or the other, or something else (neither figurative or literal)? And when can we use it? I feel it means "be how we used to be", but I am not 100% sure, because it's not really an idiom, but an expression that's often used in casual speak.
"Get back to the old times" does not sound natural to me, but either way it would be meant to be taken figuratively, as in we need to get back to how things used to be.
"We need to get back to a time when life was simpler, when people knew how to treat each other with respect!" the old man grumbled from his front porch.
If you literally mean to travel to the past through a time machine, then the expression would be "go back in time" or a similar expression:
The classic 80s movie "Back to the Future" is about a teenage boy who travels back through time to save his parents' relationship, when they were also teenagers.