Linking text in another file

Hi friends!

I used to know how to do this but have forgotten 😞

I have one file which is entirely just threaded text frames.

I am continuously polishing the text in this file.

I re-use the text in this file in some other files. sometimes all of it and sometimes on part of it.

I want to do all the polishing/corrections in one central place and have all "the children" files reflect the updates.

So in the "children" files, I guess I want to link a text frame to the test in the parent file sometimes to all of it sometimes only to part of it.

Thank you all very much

Susan