I have a small spreadsheet which displays as a landscape page on my PC.
When I try to print it out, it prints just part of it, in Portrait view?
My Lexmark printer offers portrait or landscape,
but whichever I select, the page comes out as Portrait, on an A4 page?
I might have to reduce the size, to get it all onto an A4 Landscape page
I don’t know how to do that, not being famiar with LibreOffice?
I just want to print rows 16-26 and columns B-M, not the whole sheet?
Menu Format > Page > Tab Page → choose landscape.
Then define your Print Ranges in the same Format menu.
After you chose the Landscape option in from the answer above, you will need to define the print range.
See the menu option Format/Print Range/Define