1. Tap "Edit icon" at the top of the file library and you will see a check box listed in front of each file/folder.
2. Find the particular file/folder you want to manage and tap the check box next to the file.
3. You will see the option to Add Folder and Select All in the top left corner.
The options below are Copy/Move/Rename/Delete/Actions.
4. Once you have selected a file/folder, tapping the more options button will show you the option to zip the files and folders.
5. You may also see more options for your files by tapping the drop-down menu for each file.