I am using RevenYou PPI service.
I uploaded the app, but i have no idea how can i post download link to my landing page?
If you want the file to download automatically when a button is clicked you have to upload the file to your site via FTP and then take that url and past it into the button image.
When the user clicks the image/button the file will automatically download.
Or you can put the raw url up or maybe use a anchor text.