When using R Studio, I usually just work with an .R file stacked on top of the Console. I keep the other panes (Environment, History, Files, etc) hidden.
But whenever I
The dev.new()
function will open a new plot window, which then becomes the target for all plots.
If you wish to open another window you can run the command a second time to open a second window.
dev.off()
will shut down the window (in the order they were opened by default).
You can see how to control multiple graphics devices in the documentation here.