This is MirriM's main window. Enter the source and destination locations and click the green arrow. You can follow the progress of the synchronization, and view summary statistics.
This is MirriM's options window. When you hover over an option a short explanation is given in the hint box near the bottom of the window.
Synchronization preview window
This is the syncronization preview window. It shows the operations that will be performed, and allows you to change or cancel each one.