I have created a long 78- page A5 document in LibreOffice and now need to import it into a DTP such as Scribus. How can I achieve this?
With such a long document, I’m not sure it will be really convenient to use any DTP to format it. Scribus claims it can import ODF files. However, the problem is Scribus is page-oriented while Writer automatically allocates pages as needed. In your case, you’ll have to create manually 78 pages or so and manually link text blocks to each other to accommodate you main text.
I’d rather suggest you polish the styles in the Writer document unless you have specific printing constraints (such as folding a huge sheet into a booklet where page orientation – top-down reversing – matters).
This seems a good question to ask the Scribus folk. They are the experts in Scribus.