If you add a folder for backup, Onlime backs up all subfolders in the added folder.
You can exclude a subfolder from Backup if you do not want it to be included in Backup.
How to delete a subfolder from Backup
Select a folder that contains a subfolder that you would like to exclude from Backup
Select Exclude at the bottom of the window
Mark the subfolders that you want to exclude from backup
Click Apply Changes