I do not want automatic back up to OneDrive

Often, when I click on a folder inside my Documents folder, the folder appears to be presented in the OneDirve folder and/or suggests that I back up to OneDrive.  I only want to back up selected folders/files. When I go to the Sync and Backup folder and I unselect all folders, I am not allowed to save changes. At least one folder must be selected to save changes.

The situation is annoying. How do only backup folders/files (inside the Documents folder) manually and eliminate the backup prompt described above?

Thanks in advance.