Add the files you wish to compress to the file list. Several buttons are available:
Add drive - adds an entire drive to the list
Add folder - adds a certain folder to the list
Add file - adds a certain file to the list
Remove - removes an item from the list (please make sure you select an item first)
After adding items (files, folders or entire drives) to the file list, click Next to compress the selected items.
More information about Live File Compression