File deployment to Site Assest or Style Library SharePoint

1. Add Empty Module to Solution
2. Create root folder inside empty module
3. Create Sub folders for JS, Images, CSS files.
4. Do File specific changes in Element.xml file

Sample Element.xml

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Module Name="TestDeploy" Path="TestDeploy" Url="SiteAssets">
    <File  Url="BV/Sample.txt" Type="GhostableInLibrary"/>
  </Module>
</Elements>


Solution Snap Shot:-