Opus uses a source and destination window concept. Watch the video tutorial, Working with multiple Opus windows/listers to learn about it.
Essentially, you navigate the "destination" file display to where you want the files to go, select what you want to copy/move in the "source" file display, then click the button to do it.
The two file displays can be in the same dual-display window or they can be in two separate single-display windows.
Also, you can make a "Move" button which asks you for the destination if you want to work that way. Create a button, menu item or hotkey which runs this command:
Copy MOVE TO=askFor an introduction to creating your own buttons, watch the Toolbars 1 video tutorial.