The Backup List of Folders script template is used when you have a number of folders, possibly scattered around in various places, you want to mirror into subfolders of another location.
This script template may be chosen when you create a new script.
Synk at the very least needs to know which folders you're backing up from and to. This is configured in the Locations area of the settings.
Synk will mirror each SOURCE folder into a subfolder of the DESTINATION.
Need more guidance? See Specifying Locations.
Synk can keep an archive of the older copies of files that you change or delete. This is not only convenient for when you really need last week's version of that presentation you're working on, but it's also a great safety net if you are tweaking more advanced settings and aren't confident in your changes. See the Archive section of Configuring Scripts.
At this point, you're generally in good shape! Synk uses sensible defaults, so the remaining settings are probably already what you want. Try turning on the script to begin the mirroring. If you want to approve Synk's actions before it takes them, to make sure you have it configured the way you want, you can use the Preview Proposed Actions setting.
Many other settings are available if you want to further customize the way the script works. See Script Settings.