Hi, glad you are enjoying Opus. 
(By the way, please ask one question per thread, unless the questions are closely related.)
For #1, see here.
For #2, which part are you having trouble setting up?
There is no way to make a file display function like a folder tree, in that the selection in it triggers another folder display to change folders. However, you can do something very similar by holding Ctrl and double-clicking folders, which will cause them to open in the opposite file display.
You could also have two folder trees, one for each file display, of course.