Before running ywSynch you should always take a backup of your yWriter project and exit yWriter. No liability can be taken for any loss of data that occurs, and you must take a backup to ensure that if anything goes wrong you can recover your files.
You should have your device, or its sd card or USB stick, plugged into the PC before running ywSynch (unless you are using a Dropbox to synch the documents into).
When run for the first time ywSynch will first display its Options dialogue.
On subsequent occasions, it will attempt to load the project that was open the last time it was closed.