Imported pdf text lost it's justification

Hi,

I imported a pdf manuscript into LibreOffice 5.2.5.1 that was fully-justified therein. The text has emerged in LO as left-justified. I can find no path to select all the text, or all the paragraphs, to set the text to fully-justified. I even selected a small series of lines and selected the full-justification icon in the sidebar to the right. Nothing changed.
How do I (re-) set the manuscript to fully justified?

Thanks,

First, try to get your text from PDF to arrive in a single piece, not in multiple text frames. You might find the macro from this topic useful.