1. Using mount window
Click "Mount" tab on WinMount main window, click "Mount file" on the toolbar, select an APE file.
Or Click "File -> Mount CD/DVD ROM-> Mount Audio CD" on mount window, select an APE file.
Or right-click on mount window, select "Mount CD/DVD ROM-> Mount Audio CD", select an APE file.
2. Drag APE file to mount window directly
3. Using right-click menu
Right-click an APE file, select "Mount to new drive" ( Following picture takes mou for example )