Rotate document by 90 degrees?

Hi--

New to LibreCAD.  I'm looking to annotate some DXF drawings.  They are actually architects' drawings provided as PDFs.  I used CloudConvert.com to convert to DXF.  The file, a 54 MB floor plan of a 40-50,000 sq ft medical clinic loaded into LibreCAD nicely.  :)  

The problem at hand is that the drawing loads in portrait orientation, so I would like to rotate it 90 degrees clockwise and save the change.  

Is this a standard tool in LibreCAD?  I should note that I am using v, 2.1.2 on Debian stretch, which I realize is somewhat dated.  I'm working toward upgrading to buster, which is packaged with v. 2.1.3-1.2.  Or I can use daily builds if necessary.

Thanks for the time.  

I'm on a newer version of LibreCAD, but try "Tools -> Modify -> Rotate".  The manual has a few more details.

Thanks.  I was looking in View.