The tree view is the display on the left. When you first run the Studio, this tree view contains the following items:
"Visual Zip Desktop", denoting the current display.
"My Zip Files", denoting any zip files you create and open.
"Zip Neighborhood", denoting the folders on your computer which contain zip files, and containing shortcuts to those files. To open a file in the neighborhood, simply click on it.
When you open a file, a drive icon will appear bearing the name of the zip file just opened. This icon represents the zip file and all of its contents. If the zip file has folders in it, you can click the plus sign to the left of the drive icon to see them. You can click on the drive icon or on one of the folder icons to see their contents.
To select all the files inside a folder, click on the folder icon (the drive icon is considered to be the main folder). To deselect, click again.
If you want to select all of the files inside a folder, and the folders beneath it as well, make sure there is a plus sign to the next of the folder icon.