In Windows Explorer/Finder, there are two options for keeping your folder/files locally stored.
"Download folder" and "Start/stop synchronization".
"Download folder" downloads all files in a folder just once.
This makes the files available for offline use.
While "Start/stop synchronization" is on, any new files that are uploaded from other sources (eg.: other users) are automatically downloaded without the user needing to open them.
Start/Stop Synchronization can be enabled on a Share as well, this will keep all folders/files available for offline usage.
NOTE: Upload is not affected by start/stop sync. Files are always added to the upload queue as soon as they are created on the drive