If you're using the v4.1 SCLogin module, the button should show automatically there. If you want alternative ways to show the button, you can use:
That will show all login buttons that are enabled.
{JFBCLogin provider=instagram,facebook}
That will show both the Instagram and Facebook login buttons, in that order using the default buttons defined in the JFBConnect -> Configuration area.
{JFBCLogin provider=instagram,facebook image=icon.png}
That will show both the Instagram and Facebook login buttons, in that order using the /media/sourcecoast/images/provider/facebook/icon.png (and instagram/icon.png) login button images.
I hope that helps explain, but if you're still having issues with any of the above options, just let me know.
Thanks,
Alex