Learn it the way you learn any other language. Write a program in it. Any program. Some program that is interesting to YOU. Doesn't have to be a huge project, but it should be a couple hundred lines of code. Something more than "Hello World".
No reason to try and "learn Python" unless you have some specific goal. Rather take the goal, and apply Python to it.
What will you end up with? Most likely you will end up with "C in Python" or "Java in Python", or "FORTRAN in Python". That is, whatever language you're comfortable with now will influence how you write your early Python programs. "When I want to do X in language L, I do Q. How do I do Q in Python." Which completely side steps whether doing Q in Python is a good idea in the first place.
In the end you won't be creating "idiomatic" Python code, rather you'll create working Python code, using idioms and constructs that YOU are already comfortable with while at the same time learning the Python runtime, syntax, and other boiler plate that surrounds a language.
At the same time, inevitably, some Python idioms will "sneak" their way in to your code. It can't be helped. This casual exposure of system to your way of thinking is what makes it easier to apply, because you're applying the new constructs in a domain you're familiar with.
Now, once you've finished your first project, you can start your second. Only now the fundamentals of Python are much more clear to you. In the second project, the fundamentals become second nature and now you can try and stretch to create "idiomatic" Python. Basically, now you can write "Python in Python".
Inevitably, later, when you go back to some other language, you may start trying to write "Python in Java", or something similar. Some will take, some won't. Some will be very difficult and not worth the effort, other effects may surprise you.
But starting blind, with just a language book, for me, had never worked well. I know how to program, I just need to know how to program in the L language. Rather than starting from scratch, apply the knowledge you already have and you'll end up have quicker success in the short term, and a better foundation to really learn the language in the long term.