One Way. How does one say one as a pronoun in Polish?

These days, one as a pronoun, tends to be avoided by the English masses, perhaps because it is viewed as sounding pretentious, but for most people it has been replaced by you without much confusion when in context. A Polish friend once told me there is no direct equivalent to one in Polish.  I assume the Polish don't literally say, for example, where do you buy books (when meaning where does one buy books) which would be Gdzie kupujesz książki?  Which I believe only means, where does the person you are asking buy books?  So, if that's no good and we can't ask where does one buy books? then a different phrasing is required.

Where are books bought?  Typed into Google Translate comes up with

Gdzie kupuje się książki?  kupuje is conjugated as for the third person, as you would for one as a pronoun

How is bread made?

Jak się robi chleb? again, robi is the conjugation for the third person and się pops up again

So się acts like one in these contexts?  I accept that it won't be directly equivalent*, but I'm think it might be near enough for me to get my head around.

On the subject of one: I often want to say things like, I've heard that... or I've been told that... which in French is on ma dit... (one told me...) but I've been told that the Polish equivalent phrase is:

Słyszałem, że... or słyszałam, że...

Which I thought I'd note down here for no other reason than I associate the phrase with one through use of the French phrase.  I doubt anyone else would follow that logic, but one never knows.

*I believe się means self , themselves, oneself, when used as a reflexive pronoun