First make sure that you have network discovery and file sharing on. You can change these settings through network and sharing center in control panel. (They are enabled by default if you're on a private network - home or work)
Then open the 'properties' windows for the folder you want to share and choose 'share' from sharing tab. There you can add and set permission for anyone who needs to have access to the folder.
You can also use the 'advanced sharing' from the same tab for more options.
I've never heard of the app, but basically you shouldn't need extra software for file sharing in windows.