Second monitor

[Peter Flynn]

I have a Dell XPS desktop and my regular monitor is connected via the 
HDMI socket.

I want to set up a second monitor in *portrait* mode — I do a lot of 
publishing work, so having a display I can show a full page on the right 
way up would be useful.

I have an unused second screen with DVI and VGA ports, and the desktop 
has a DVI port.

Before I rush out and buy cable, can I connect this second screen using 
the DVI ports this way, and if so, will Ubuntu 18 detect it (or can I 
configure it in the X settings) so I can export DISPLAY=:1 or whatever, 
and then issue an xrandr -o left command or use some utility to rotate 
the second monitor image.

If that's possible, what would I need to do to force a program (eg 
okular) to display its image full-screen on the second monitor?

P