If you have selected files in Copywhiz using File Explorer (Windows Explorer), then go to the destination folder. Right-click inside the folder, choose Copywhiz → Paste Advanced to open the Copywhiz window and click on the 'Advanced Settings' button as shown in the picture below.
If you have Copywhiz's main window already open, then you can directly click on the 'Advanced Settings' button as shown in the picture below.
Press the OK button and click on the 'Paste Now' button to finally paste all the selected files to a single folder. A sound plays, indicating the successful completion of a file copy task.